Preparation of co-prepolymers from mono-substituted fluorinated monomers and tetrahydrofuran

ABSTRACT

This application is directed to novel fluorinated polymers and prepolymers derived from mono-substituted oxetane monomers having fluorinated alkoxymethylene side-chains and the method of making these compositions. The mono-substituted fluorinated oxetane monomers having fluorinated alkoxymethylene side-chains are prepared in high yield by the reaction of a fluorinated alkoxides with either 3-halomethyl-3-methyloxetane premonomers or aryl sulfonate derivative of 3-hydroxymethyl-3-methyloxetane premonomers. Preparation of a mono-substituted 3-bromomethyl-3-methyloxetane premonomer via a simple, high yield process amenable to commercial scaleup is also disclosed. The fluorinated oxetane monomers of this invention can be readily homo/co-polymerized in the presence of a Lewis acid and polyhydroxy compounds to obtain hydroxy-terminated polyether prepolymers having fluorinated alkoxymethylene side chains. Additionally, the fluorinated oxetane monomers can be copolymerized with non-fluorinated monomers such as tetrahydrofuran to give polyether prepolymers with improved hydrocarbon compatibility. These prepolymers are polydisperse and exhibit number average molecular weights from 5,000 to about 50,000. These prepolymers are amorphous oils with primary hydroxy end-groups and thus function efficiently as the soft block for the synthesis of a variety of thermoset/thermoplastic elastomers and plastics having the characteristics of very low surface energy, high hydrophobicity, low glasss transition temperature and low coefficient of friction. The polyurethanes derived from the prepolymers of this invention are elastomeric and, in addition to the above characteristics, exhibit high moisture resistance, high tear strength and excellent adhesion to a variety of substrates.

CROSS REFERENCE TO RELATED APPLICATIONS

This Application is a Divisional Application of our parent applicationSer. No. 08/371,914, filed Jan. 12, 1995, now abandoned, which in turnis a Continuation-In-Part application of application entitled"Preparation and Polymerization of Perfluoroalkoxy Alkylene Oxides toPrepare Hydrophobic Ethers", Ser. No. 08/206,618, filed Mar. 7, 1994,now abandoned which in turn is a Continuation application of applicationof that same title, Ser. No. 08/080,614, filed Jun. 21, 1993, nowabandoned, which in turn is a Continuation application of Ser. No.07/911,461, filed Jul. 10, 1992, now abandoned.

FIELD

This invention relates to prepolymer compositions and the polymersderived therefrom, oxetane monomers having asymmetric mono-substitutedpendant fluorinated alkoxymethylene groups as the prepolymer precursors,methods of preparing the precursor monomers and methods ofpolymerization of the prepolymers to form fluorinated elastomers. Thehydroxy-terminated prepolymers have a polyether backbone and are useful,inter alia, for the preparation of polyurethane elastomers, thermosetplastics and coatings. These compositions exhibit hydrophobicproperties, very low surface energies, low glass transitiontemperatures, low di-electric constants, high abrasion resistance andtear strength, low coefficient of friction, high adhesion and lowrefractive indices.

BACKGROUND

Fluorinated Elastomers

Fluorinated polymers enjoy widespread use as hydrophobic, oleophobiccoatings. These materials exhibit excellent environmental stability,high hydrophobicity, low surface energy and a low coefficient offriction, and are used in a number of applications ranging fromnon-stick frying pans to optical fiber cladding.

Most fluoropolymers, however, are plastics that are difficult toprocess, difficult to apply and are unsuitable as coatings for flexiblesubstrates due to their high rigidity. One example of a widely usedfluorinated material is Teflon, a polytetrafluoroethylene. Teflon isdifficult to process in that it is a rigid solid which must be sinteredand machined into its final configuration. Commercial application ofTeflon as a coating is complicated by its poor adhesion to a substrateand its inability to form a continuous film. As Teflon is insoluble,application of a Teflon film involves spreading a thin film of powderedTeflon onto the surface to be coated, and thereafter the powdered Teflonis sintered in place resulting in either an incomplete film or havingmany voids. As Teflon is a hard inflexible plastic, a further limitationis that the substrate surface must be rigid otherwise the Teflon willeither crack or peel off.

A limited number of commercial fluoropolymers, such as Viton, possesselastomeric properties. However, these materials have relatively highsurface energies (as compared to Teflon), poor abrasion resistance andtear strength, and their glass transition temperatures are still highenough (>0° C. for Viton) to significantly limit their use in lowtemperature environments.

Accordingly there is a need for fluoroelastomers having hydrophobicproperties, a surface energies and coefficients of friction at leastequivalent to the fluorinated plastics (such as Teflon). Further, suchfluoroelastomers must have high adhesion, high abrasion resistance andtear strength, low index of refraction and a low glass transitiontemperature so that it is suitable for any foreseeably low temperatureenvironment use. Additionally, there is a need for fluoroelastomers thatare easily produced in high yields and easy to use. Currently, there areno fluoroelastomers that satisfy all of these needs.

Premonomers

We have discovered and recognized that the conspicuous absence offluorelastomers in the art exhibiting all of the above enumeratedproperties can be understood upon analysis of the upstream end of thecurrent processes for synthesis of fluoropolymers and plastics. Thekinds and properties of the premonomers currently used in turn result inthe limitations in the properties of the monomers, which further limitthe diversity and properties of currently known fluoropolymers andfluoroelastomers.

It is known that a haloalkyl oxetane can be substituted in the3-position with methyl groups containing energetic functional groupssuch as nitrato, azide, nitro and difluoroamino. The polymerization ofthese substituted oxetanes in the presence of polyhydroxy aliphaticcompounds produces hydroxy-terminated prepolymers having a polyetherbackbone with pendant energetic groups.

The use of substituted oxetanes as a starting material for theproduction of polyethers is not new. However, the theme running throughthe art is that bis-substituted oxetanes are of primary interest andcommercial importance. This is understandable in that the bis-haloalkyloxetane starting material or premonomer is easily produced, whereas themono-substituted 3-haloalkyl methyl oxetane premonomer is difficult andexpensive to produce. There is little teaching in the art for guidanceon easy, inexpensive methods of preparation of 3-haloalkyl-3-methyl(mono-substituted) oxetane premonomers or their use in synthesizingmono-substituted fluorinated oxetane monomers.

Bis-haloalkyl oxetane premonomers as a starting material are describedin Falk et al. (U.S. Pat. No. 5,097,048). Falk disclose 3,3-bisperfluoroalkyl oxetane monomers derived from bis-haloalkyl oxetane as astarting material. Reaction of the bis-haloalkyl oxetane with aperfluoroalkyl thiol, a perfluoroalkyl amine, a perfluoroalkanol, or aperfluoroalkyl sulfonamide will produce the 3,3'-bis perfluoroalkyloxetane monomer described in this reference.

Bis-haloalkyl oxetane premonomers are readily commercially available andtheir derivatives are fairly well covered in the art. Mono-haloalkyloxetanes, however, are rarely mentioned in the art, appearing only as anincidental comparison in a more complete investigation of thebis-haloalkyl oxetanes. The lack of teaching regarding themono-substituted fluorinated alkoxymethylene oxetanes (herein "FOX"compounds for Fluorinated Oxetane), and their relative commercialunavailability, is undoubtedly due to the fact that mono-substitutedhaloalkyl oxetanes are very difficult and expensive to make. Currentprocesses for the production of mono-substituted haloalkyl oxetanepremonomers, such as 3-bromomethyl-3-methyloxetane ("BrMMO"), aretypified by low yields, long, complicated synthetic schemes and the useof toxic, expensive chemicals to convert 1,1,1-tris(hydroxymethyl)ethane("TME") into BrMMO.

In these processes, TME is reacted with diethyl carbonate to produce thecorresponding cyclic carbonate. This in turn undergoes decarboxylationupon thermal decomposition at 160° C. to provide3-hydroxymethyl-3-methyloxetane ("HMMO"). The HMMO is converted to theprimary chloro compound with carbon tetrachloride and triphenylphosphine. Reaction of the chloro compound with sodium bromide in methylethyl ketone results in S_(N) 2 displacement of the chlorine to produceBrMMO. This scheme is commercially impractical in that it is both laborintensive and requires expensive, toxic chemicals. Consequently, thesedisadvantages have precluded the use of mono-substituted fluorinatedoxetane (FOX) monomers that may be derived from mono-substitutedhaloalkyl oxetanes, such as BrMMO, and production of polymer productsthereof.

Accordingly, there is a need for a mono-substituted fluorinatedalkoxymethylene oxetane monomer with a fluorinated side-chain capable ofproducing prepolymers and polymers having desirable properties, such asoil and water repellency, at least comparable to the bis-substitutedperfluoroalkyl oxetanes known in the literature. Further, there is alsoa need for a high yielding reaction pathway for production of themono-substituted haloalkyl premonomer, characterized by a minimumproduction of by-products, and a commercial feasibility for high volume,high yield production without the excessive labor and materials costsassociated with the currently known processes.

Monomers and Prepolymers

The most important criteria in the development of release (i.e.,non-stick), high lubricity coatings is the minimization of the freesurface energy of the coating. Free surface energy is a measure of thewettability of the coating and defines certain critical properties, suchas hydrophobicity and adhesive characteristics of the material. For mostpolymeric surfaces the surface energy (dispersion component) can beexpressed in terms of the critical surface tension of wetting γ_(C). Forexample, the surface energy of Teflon (represented by γ_(C)) is 18.5ergs/cm², whereas that of polyethylene is 31 ergs/cm². Consequently,coatings derived from Teflon are more hydrophobic and non-stick thanthose derived from polyethylene. A substantial amount of work has beendone by the coating industry to develop coatings with surface energieslower than or comparable to Teflon while at the same time exhibitingsuperior adhesion characteristics.

The literature teaches that in order to prepare coatings with thedesirable low surface energy, the surface of the coating must bedominated by --CF₃ groups. Groups such as --CF₂ --H and --CFH₂ increasethe surface energy of the material. The importance of the number offluorine atoms in the terminal group (i.e., the group present on thesurface) was demonstrated in Zisman et al., J. Phys. Chem., 1953, 57,622; ibid. J. Colloid Sci., 1954, 58, 236; Pittman et al., J. PolymerSci., 1968, 6, 1729. Materials with terminal --CF₃ groups exhibitedsurface energies in the neighborhood of 6 ergs/cm², whereas similarmaterials with terminal --CF₂ H groups exhibited values in theneighborhood of 15 ergs/cm², more than twice the value for the materialwith terminal --CF₃ groups. Teflon incorporates the fluorine moieties onthe polymer backbone and does not contain pendant --CF₃ groups.Consequently, Teflon does not exhibit surface energies as low aspolymers having terminal perfluorinated alkyl side-chains.

A critical requirement in the production of an elastomer is that theelastomer have large zones, or "soft segments", where little or nocrosslinking occurs and where the polymer conformation is such thatthere is little or no compaction of the polymer as a result ofcrystallization. Intermediate of these soft zones are "hard blocks"wherein there may be significant hydrogen bonding, crosslinking andcompaction of the polymer. It is this alternating soft block and hardblock which gives the polymer its elastomeric properties. The longer thesoft segment, the more elastic the elastomer.

We have discovered that an improved route to producing elastomers is toproduce homo- or co-prepolymers characterized as non-cross linked,assymetrical, hydroxy-terminated, linear oligomers having from about 10to about 500 carbons, preferrably 20 to about 200 carbons. Theseprepolymers substantially retain their integrity in subsequentpolymerizing reactions to provide the soft segment zones of theresulting polymers which, in combination with the hard blocks formedduring polymerization, produce good elastomers. We have found that theliterature does not have any showing of homo- or co-polymerization ofeither the bis or the mono-substituted fluorinated alkoxymethyleneoxetanes to produce soft segment containing prepolymers required forproduction of elastomers. Accordingly, there is a need for fluorinatedoxetane (FOX) monomers having a side-chain with an omega or terminalperfluorinated alkyl group, which monomers are capable ofhomo-polymerization or copolymerization to produce the soft segment,herein "FOX prepolymers", necessary for a fluorinated elastomer.

Further, in order for the hydroxy-terminated prepolymer with afluorinated side-chain (i.e., FOX prepolymers) to be useful, it musthave a functionality of at least 2. Presence of non-functional ormono-functional materials in the prepolymers result in coatings withpoor mechanical and surface properties. Consequently, these coatingshave limited commercial value. Non-functional materials, mainly cyclictetramers and trimers, are formed during the ring opening polymerizationfrom chain "back-biting". Monofunctional materials, on the other handare formed due to counter-ion terminations, such as diethyl ether andfluoride ion terminations.

Falk et al. (U.S. Pat. No. 5,097,048) disclose the synthesis ofbis-substituted oxetane monomers having perfluoro-terminated alkyl groupside chains from bis-haloalkyl oxetane, the glycols havingperfluoro-terminated alkyl group side chains derived therefrom,including related thiol and amine linked glycols and dimer diols. Mostof the fluorinated side-chains are attached to the glycol unit by eithera thio, an amine or a sulfonamide linkage. Only a few of their examplesdescribe glycols with perfluoro-terminated alkoxymethylene side-chains.

Falk et al. (EP 03 48 350) report that their process yieldsperfluoro-terminated alkyloxymethylene neopentyl glycols composed of amixture of (1) approximately 64% of the bis-substitutedperfluoro-terminated alkyl neopentyl glycol, and (2) approximately 36%of a mono-substituted perfluoro-terminated alkyl neopentyl glycolproduct with a pendant chloromethyl group. Evidently, themono-substituted product results from incomplete substitution of thesecond chloride on the bis-chloroalkyl oxetane starting material.Consequently, as noted from the Zisman and Pittman work above, thepresence of the --CH₂ Cl as a side-chain significantly increases thesurface energy of coatings made from these polymers thus reducing thehydrophobicity and oleophobicity of the coating.

Not surprisingly, it is understandable that Falk et al. (U.S. Pat. No.5,097,048) discourages the use of the mono-substituted glycol for thepreparation of low surface energy coatings, since the monosubstitutedglycol as produced from bis-chloroalkyl oxetanes would necessarily havea residual chloromethyl group still attached to the 3-carbon because ofthe incomplete substitution of the bis-haloalkyl moieties on thestarting material. Accordingly, their teaching that the polymerderivatives from mono-substituted glycols do not produce a coatingexhibiting the desired properties, to the same extent as coatingsderived from bis-substituted glycols is premised on a lower free surfaceenergy for the bis-substituted compounds as compared to Falk'smono-substituted compounds (Falk, U.S. Pat. No. 5,097,048, column 1,lines 43-50). However, they ignore the fact that the residualchloromethyl group may serve to increase the free surface energy of theFalk mono-substituted compound more so that the fact it is onlymono-substituted in a R_(f) function.

Moreover, the reference cited by Falk et al. in the '048 patent, J. Org.Chem., 45 (19) 3930 (1980), stating at line 33 that "mono-fluoroalkyloxetanes containing oxygen have been reported" is misleading in that thereference cited discusses oxetanes substituted with --CH₂ F side chains(i.e., (monofluoro)alkyl oxetanes) and not alkoxymethylene side chainswith terminal perfluoroalkyl groups. Hence, this reference will not leadto materials with low surface energies and is not relevant to thecompounds of this invention.

Falk et al. (U.S. Pat. No. 5,045,624) teaches preparation of dimers withfluorinated side-chains having thio linkages, but not of dimers withfluorinated ether side-chains. This is because his synthesis route forpreparing dimers with thio linkages cannot be used for the synthesis ofdimers with ether linkages. In other words, Falk et al. does not teachpreparation of long chain polyethers with fluorinated ether side-chains.

Falk et al. (U.S. Pat. No. 4,898,981) teaches incorporation of theirbis-substituted glycols into various foams and coatings to impart tothem the desired hydrophobicity and oleophobicity. Classic polyurethanechemistry shows that while a plastic may form by reaction of Falk'sglycols with the diisocyantes, elastomers can not form since there is nolong chain soft segment. As noted above, such a soft segment is neededfor the formation of an elastomer. Since the Falk et al. compounds areonly one or two monomer units long, it is clearly too short to functionas a soft segment for the formation of a polyurethane elastomer. In Falket al., the fluorinated glycol and isocyanate segments alternate, withthe fluorinated glycol segments being nearly the same size as theisocyanate segments. It is well known that such a polymer structure willnot yield elastomers.

None of the Falk et al. references teach or show a homo-prepolymer orco-prepolymer made from bis perfluoro-terminated alkoxymethyleneoxetanes, nor polyurethanes derived thereform or from the correspondingglycols. All of their polyurethanes are made directly from the thiollinked monomers and dimers and not via a prepolymer intermediate. In theexamples provided in Falk et al. (U.S. Pat. No. 5,045,624), particularlywhere the perfluoro-terminated side-chains are large and for all of thedimers, all have thiol linkages; no ether side-chains are shown. Thepolyurethanes disclosed by Falk et al. (U.S. Pat. No. 4,898,981) aremade from the perfluoro-terminated alkylthio neopentyl glycol. They donot teach, show or suggest producing a polyurethane from theperfluoro-terminated alkoxy neopentyl glycol monomer, nor do theysuggest, teach or show the types of prepolymers and polymers that can beprepared from the mono-substituted 3-perfluoroalkoxymethylene-3-methyloxetanes (i.e., FOX monomers). However, Falk et al. (U.S. Pat. No.5,097,048) in their Example 12 show a polyether prepolymer prepared froma bis-substituted perfluoroalkylthio oxetane. The prepolymer obtainedwas a white waxy solid, clearly not an elastomer. No characterization asto, nature of the end groups, polydispersivity, equivalent weights, etc.of the the waxy solid was given. Absent such a characterization, it isunknown as to whether Falk et al.s' material may be further reacted withan isocyanate to produce a polyurethane polymer. No examples of thepreparation of a polymer from any prepolymer is given.

Manser (U.S. Pat. No. 4,393,199) teaches a method for polymerizingoxetane monomers by employing an initiator/catalyst system composed ofan alkyl diol and a Lewis acid catalyst, BF₃ etherate. Manser teachesthat not all oxetane monomers can be homopolymerized and that the rateof polymerization of bis-substituted oxetane monomers is dependent uponthe nature of the substituent at the 3 position on the monomer. Manserdoes not teach or suggest the polymerization of mono-substitutedfluorinated alkoxymethylene oxetanes to produce low viscosity, welldefined, difunctional hydroxy-terminated assymetric prepolymers withfluorinated side-chains, nor does he suggest that the prepolymer derivedfrom that polymerization could be cured with diisocyanates to obtainelastomers having exceedingly low surface energies.

Vakhlamova (Chem. Abst. 89:110440p) teaches synthesis of oxetanecompounds substituted at the number 3 carbon of the oxetane with --CH₂O--CH₂ --CF₂ --CF₂ --H groups. The terminal alkyl portion of thissubstituent is thus: --CF₂ CF₂ --H in which the terminal or omega carbonbears a hydrogen atom. As discussed supra, the Zisman and Pittman worksshows that the presence of the hydrogen significantly increases thesurface energy of the polymer derived from these monomers. Falk et al.(U.S. Pat. No. 5,097,048) also recognizes that surface energy increaseswith the hydrogen atom on the terminal carbon by stating that"fluoroalkyl compounds which are terminally branched or containomega-hydrogen atoms do not exhibit efficient oil repellency". Further,Vakhlamova focuses on the bis-substituted monomer as he hydrolyzes andpolymerizes only the bis-substituted monomer.

A characteristic of the polymers formed from the polymerization of thebis-substituted oxetanes of Falk et al., and the other proponents ofbis-substituted oxetanes is that the resulting products are crystallinesolids. The bis side-chains are highly ordered and symmetric.Consequently, they pack efficiently to form a crystalline structure. Forexample, a prepolymer prepared from 3,3-bis(chloromethyl)oxetane is acrystalline solid that melts in the neighborhood of 220° C. Thissignificantly affects the commercial use of these polymers as either orboth mixing and elevated temperatures will be required in order todissolve or melt the Falk et al. polymer for further polymerization orapplication.

Polymerization of the bis-substituted perfluorinated alkoxymethyleneoxetanes has received little attention in the art. Moreover, thepolymers derived from the bis-substituted perfluoroalkylthiol oxetanesare waxy solids and will not function as a soft segment in thepreparation of commercially useful elastomers and coatings. Further, theability of a bis-substituted oxetane monomer to homopolymerize appearsto be dependent upon the nature of the side-chain at the 3 carbon withno assurance such polymerization will occur, the difficulty ofpolymerization apparently being due to the interference by the 3-carbonside-chains. Polymerization, and the products of polymerization, of thebis monomer accordingly are unpredictable and inconsistent.

Accordingly, there is a need in the art for a fluorinated elastomerproduct having low surface energies and the Other properties enumeratedabove, and a production strategy therefor, beginning with a premonomerproduction process that is easy and inexpensive, to produce anassymetrical mono-haloalkyl methyl oxetane premonomer, which uponfurther reaction produces an oxetane monomer having a single fluorinatedside-chain, which mono-substituted fluorinated monomer is capable ofhomopolymerization and copolymerization to produce an essentiallynon-cross-linked soft segment, difunctional, linear, assymetricprepolymer for further reaction to produce fluorinated elastomers andthermoset plastics, resins and coatings having hydrophobic properties,low surface energy, very low glass transition temperatures, lowdi-electric constants, high abrasion resistance and tear strength, highadhesion and low refractive indices.

THE INVENTION

Objects:

It is among the objects of this invention to provide fluorinatedelastomers and thermoset plastics with fluorinated alkoxymethyleneside-chains having good hydrophobic properties, low surface energies,very low glass transition temperatures, low di-electric constants, highabrasion resistance and tear strength, high adhesion and low refractiveindices;

It is an object of this invention to provide a process for making andusing fluorinated elastomers and thermoset plastics with fluorinatedalkoxymethylene side-chains having low surface energies, very low glasstransition temperatures, low di-electric constants, high abrasionresistance and tear strength, high adhesion and low refractive indices;

It is an object of this invention to provide fluorinated elastomers andthermoset plastics with fluorinated alkoxymethylene side-chains havinggood hydrophobic properties, low surface energies, very low glasstransition temperatures, low di-electric constants, high abrasionresistance and tear strength, high adhesion and low refractive indicesfrom the process of this invention;

It is another object of this invention to provide the compositions inwhich the fluorinated elastomers and plastics of this invention are usedas fouling and ice release coatings, drag reduction coatings, moisturebarrier coatings; catheters; artificial prosthesis components such asjoints, hearts, and valves; contact lenses; intraocular lenses; films,paints; adhesives; non-transfer cosmetics; water repellent coatings;oil/stain resistant coatings; incindiary binders; lubricants, and thelike; and processes for the production and use of such coatings,adhesives, binders and compositions;

It is another object of this invention to provide a hydroxy terminatedpolyether prepolymer having asymmetric, alkoxymethylene side-chains withterminal perfluorinated alkyl groups for the production of theelastomers and thermoset plastics of this invention;

It is another object of this invention to provide a hydroxy terminatedpolyether co-prepolymer having asymmetric, mono-substituted fluorinatedalkoxymethylene side-chains with terminal perfluorinated alkyl groupsand a backbone composed of FOX monomer segments and of tetrahydrofuran(THF) segments for the production of the elastomers and thermosetplastics of this invention;

It is another object of this invention to provide the use of theprepolymers and co-prepolymers of this invention as, and as components,inter alia, in: coating compositions; lubricants; and pump oils whichimpart hydrophobic properties, low surface energies, low coefficient offriction, very low glass transition temperatures, low di-electricconstants, high abrasion resistance and tear strength, high adhesion andlow refractive indices to these resins, oils, lubricants and coatings;

It is another object of this invention to provide the process for theproduction of the hydroxy-terminated fluorinated polyether prepolymerhaving asymmetric, fluorinated alkoxymethylene side-chains of thisinvention;

It is another object of this invention to provide processes for theproduction of hydroxy-terminated fluorinated co-prepolymers having,fluorinated alkoxymethylene side-chains and a backbone composed of FOXmonomer segments and THF segments;

It is another object of this invention to provide prepolymer andpolymeric products of the processes of homopolymerization and ofcopolymerization of the FOX monomers of this invention;

It is another object of this invention to provide products of theprocesses of copolymerization of the FOX monomers of this invention withTHF;

It is another object of this invention to provide FOX monomers derivedfrom mono-haloalkyl 3-methyloxetanes, the monomers beingmono-substituted at the 3 carbon with a fluorinated alkoxymethyleneside-chain for the production of the prepolymers of this invention, andprocesses for the production, use and polymerization thereof;

It is another object of this invention to provide the product of theprocesses for production of FOX monomers of this invention;

It is another object of this invention to provide processes for makingFOX monomers derived from mono-haloalkyl-3-methyloxetanes, the FOXmonomers being mono-substituted at the 3-carbon with a fluorinatedalkoxymethylene side-chain for the production of the prepolymers of thisinvention;

It is another object of this invention to provide a relatively simpleand inexpensive process for the production of3-haloalkyl-3-methyloxetane as a premonomer for the FOX monomers of thisinvention;

It is another object of this invention to provide products from theprocesses for the production of 3-haloalkyl-3-methyloxetane as apremonomer of this invention; and

Still other objects of the invention will be evident from theSpecification, drawings and claims hereof.

DICTIONARY

Aprotic Solvent: A solvent that does not donate a proton.

BrMMO: Acronym for 3-bromomethyl-3-methyl oxetane, the preferredpremonomer of this invention.

Contact Angle: The obtuse or internal angle between the surface of aliquid and the surface of an object in contact with the liquid. A highcontact angle corresponds to high hydrophobicity.

FOX Copolymerization: Reaction of a FOX monomer with a either adifferent FOX monomer or a non-fluorinated monomer to produce a FOXco-prepolymer.

DSC: Acronym for differential scanning calorimeter, a device used fordetermining a compunds glass transition temperature.

Elastomer: A polymeric material, such as rubber, which can be stretchedunder low stress to at least twice its original length and, uponimmediate release of the stress, will return with force to itsapproximate original length.

FOX: Acronym for Fluorinated Oxetane. As used in the disclosure of thisinvention the term "FOX" is normally preceeded by a number; e.g., 3-FOX,7-FOX, etc. The numerical designation indicates the number of fluorinemoieties on the single fluorinated side chain on the 3-carbon of the FOXmonomer.

GLC: Acronym for gas-liquid chromatography. A device and method used asa separation technique to determine purity and percent conversion ofstarting materials.

GPC: Acronym for gel permeation chromatography. A device and method usedto determine molecular weight.

HMMO: Acronym for 3-hydroxymethyl-3-methyloxetane, an intermediate inthe production of the arylsulfonate oxetane premonomer.

FOX Homopolyerization: Reaction of a FOX monomer with itself to producea Fox homo-prepolymer.

Hydrophobicity: The degree to which a substance lacks an affinity for,or repels, or fails to absorb water.

Lewis Acid A substance that can accept an electron pair from a base;thus AlCl₃ and BF₃ are Lewis acids.

Mono-substituted Oxetane: In the context of this invention, broadly anon-bis substituted oxetane compound. More specifically, it refers tothe 3-halomethyl-3-methyloxetane premonomers and FOX monomers of thisinvention where the 3-carbon of the oxetane ring is substituted withonly one fluorinated side chain and the other 3-carbon side group is anon-fluorinated moiety; e.g., a methyl or ethyl group.

FOX Monomer: In the context of this invention, a mono-substitutedfluorinated oxetane or FOX.

Phase Transfer Catalyst: Effectuates or mediates reactions in adual-phase heterogeneous reaction mixture.

FOX Premonomer: Those 3-haloalkane-3-methyloxetane compounds which uponreaction with fluorinated alkoxides yields the FOX monomers of thisinvention.

FOX Prepolymer: A hydroxy terminated, polyether oligomer comprising fromabout 20 to about 300 FOX or FOX/THF monomer units which, upon reactionwith a polyisocyanate will yield polyurethane elastomers.

Tetrahydrofuran: A commercially available 5-membered cyclic ether,abbreviated THF.

Acronym for 1,1,1-tris(hydroxymethyl)ethane, the starting material forthe BrMMO premonomer synthesis.

BRIEF DESCRIPTION OF DRAWINGS

The invention is illustrated in part by reference to the drawings inwhich:

FIG. 1A is a photograph of contact angle (110°) of drops of water on aTeflon surface.

FIG. 1B is a photograph of the contact angle (145°) of drops of water ona FOX polymer of this invention.

FIG. 2 is a summary of the polymerization reaction of FOX monomers bycationic ring opening reaction.

SUMMARY

This invention is directed to mono-haloalkyl oxetane premonomers,mono-substituted oxetanes monomers having fluorinated alkoxymethyleneside-chains derived from these premonomers, hydroxy-terminatedprepolymers derived from these monomers, and polymers produced fromthese prepolymers, as well as the synthesis processes associated witheach, and the use of the premonomers, monomers, prepolygers and ultimatepolymers, both directly and as components of compositions.

The premonomers, monomers, polyether hydroxy-terminated prepolymers andresulting compositions thereof are particularly useful for thepreparation of polyurethane elastomers, thermoset plastics and coatingswhich exhibit a wide variety of useful properties including, interalia,hydrophobic properties, low surface energies, low glass transitiontemperatures, low dielectric constants, high abrasion resistance andtear strength, low coefficients of friction, high adhesion and lowrefractive indices. A major application is for non-stick coatings, inthat the adhesion of the polymer of this invention is better thanTeflon, the surface energy is lower, the application is easier, and theapplied film is flexible with good abrasion resistance and tear strengthpermitting application to both flexible and rigid surfaces. Examples areanti-fouling coatings, ice release coatings, flexible optical fibercladding, conduit and aqueduct coatings or linings, surface coatings,anti-graffity coatings, automotive top-coat compositions (e.g., carwax), particularly at low temperatures due to low glass transitiontemperatures on the order of -40 to -50° C. The low index of refractionand good oxygen permeability, coupled with the optical clarity of someof the elastomers produced from the prepolymers make them useful forcontact lenses and intraocular lenses. Of course, uses for elastomersare well known, and the improved properties of the elastomers of thisinvention permit an even wider range of uses.

As noted above, we have discovered an improved route to producingfluorinated elastomers. Our discovery includes an improved, two-stepprocess for the synthesis of a mono-substituted haloalkyl oxetanepremonomer which is easier and less expensive than currently knownprocesses. The premonomers in turn are used in another novel process toproduce mono-substituted fluoroalkyl oxetanes (FOX monomers). Further,the process is so versatile, that bis-fluoroalkyl oxetanes may beproduced by this process in high yields.

The monomers are used to produce homo- or co-prepolymers characterizedas non-cross linked, assymetrical, hydroxy-terminated, linear oligomershaving from about 10 to about 500 carbons, preferrably 20 to about 200carbons, i.e., FOX prepolymers. These prepolymers are crucial to theproduction of fluorinated elastomers in that they substantially retaintheir integrity in subsequent polymerizing reactions (e.g., reactionswith diisocyanates or polyisocyanates) to provide the soft segmentblocks of the resulting polymers which, in combination with the hardblocks formed during polymerization, produce good elastomers. While thebackground does not have any showing of homo- or co-polymerization ofeither the bis or the mono-substituted fluorinated alkoxymethyleneoxetanes to produce prepolymers containing soft segment required forproduction of elastomers, the processes of our invention will readilypolymerize both mono- and bis-substituted FOX monomers. The reactionmechanism of our process will produce prepolymers from bis fluoroalkyloxetane monomers in high yields as well as from monosustituted FOXmonomers.

We have also discovered in the reactions and processes of the backgroundthat the presense of two, symmetric side chains, as in thebis-substituted oxetane monomers of Falk et al. result in slowerreaction rates and lower yields. Without wishing to be bound by theory,we presently believe this is due to the presense of the two side groupsof the bis-monomer compounds sterically hindering the initiation and thepropagation reaction of the growing prepolymer chain. Whereas thebackground shows polymerization of just the thio-linked bis-oxetanemonomer (and no ether-linked side-chains) such polymerization isdifficult to initate and when successful, results in a prepolymer thatis crystalline. The resulting prepolymers are more symmetric and moreregular than prepolymers produced from mono-substituted FOX monomersand, therefore, pack more efficiently to form crystalline materials.

Surprisingly, and contrary to the teachings of the prior art, twofluorinated side chains are not necessary to impart high levels ofhydrophobic and low surface energy properties. The art teaches that themore fluorine, the better the properties, however, the presense of twoidentical perfluoro-terminated side chains lead to steric hindrance andformation of crystalline materials, a morphology which makes furtherprocessing difficult. In contrast, we believe the asymmetry presented bythe single (mono) group having fluorinated substituents of the FOXmonomers of our invention which upon polymerization prevents theregularity in packing and results in amorphous prepolymers.

Unexpectedly, although the homo- and co-prepolymers composed of FOXmonomers and of FOX/THF co-monomers contain less than half of the numberof fluorine moieties as a bis-substituted prepolymer, they surprisinglyproduce polymers that have similar surface energies as a polymer derivedfrom prepolymers having two fluorinated side-chains. Further, eventhough the FOX/THF prepolymers of our invention contain less fluorinethan the FOX prepolymers of our invention, the elastomers produced fromthe FOX/THF prepolymers surprisingly exhibit surface and physicalproperties comparable to the elastomers produced from the FOXprepolymers.

We have discovered a polymerization process which virtually eliminatesthe formation of undesireable by-products. The presence ofnon-functional or mono-functional materials in the prepolymers result incoatings with poor mechanical and surface properties. Consequently,these coatings have limited commercial value. Non-functional materials,mainly cyclic tetramers and trimers, are formed during the ring openingpolymerization from Chain "back-biting". Monofunctional materials, onthe other hand are formed due to counter-ion terminations, such asdiethyl ether and fluoride ion terminations. The processes of thisinvention are unique in their lack of by-product production. Productionof cyclic tetramers and monofunctional prepolymers are almostundetectable.

1. Monomers

a) BrMMO Pre-monomer

The FOX monomers of this invention are preferably derived from3-bromomethyl-3-methyloxetane ("BrMMO"). While the preferred leavinggroup on the mono-substituted haloalkyl oxetane is bromine, otherhalogens such as chlorine and iodine, as well as aryl sulfonates may beused. Reaction with BrMMO provides a convenient route in the preparationof 3,3-asymmetrically substituted oxetanes. BrMMO can be converted intoa large variety of asymmetrical substituted oxetanes via SN₂displacement with energetic groups such as nitro, nitrato, azido, amino,difluoroamino and nitroamino being introduced. Monomers for polymerradical cure coatings such as oxetanes substituted at the 3-positionwith vinyl, allyl, homoallyl and styryl groups can also be prepared.

As described in the background, the processes currently practiced forthe production of 3-haloalkyl-3-methyl oxetanes, and more particularlyto the production of BrMMO, are typified by low yields, side-reactionimpurities, long, multi-step synthetic schemes and the use of expensive,toxic chemicals with hazardous materials and hazardous waste handlingand disposal problems. These represent significant obstacles in thecommercial scale-up of these processes. Consequently,3-haloalkyl-3-methyl oxetane is not currrently commercially available.

The process for the production of BrMMO of this invention, however, usescommon inexpensive starting materials and provides BrMMO cleanly in highyields with only two steps. The process is novel in that it incorporatesan in-situ generation of HBr. Unexpectedly, the in-situ generation ofHBr permits the use of an alcohol with a molecular weight greater thann-butanol to produce a primary bromide in high yield with noby-products.

In the first step, as shown in Formula 1 below,3-bromo-2-bromomethyl-2-methylpropyl acetate 2 (the dibromoacetate of1,1,1-tris(hydroxymethyl)ethane or TME) is formed via bromination of theTME in glacial acetic acid with in-situ generated HBr. The HBr is formedin situ from the reaction of sulfuric acid with sodium bromide. Reactiontemperature may range from about 100° to about 130° C., preferably about120° C. We have discovered that the formation of the triacetate of TMEunexpectedly more easily undergoes displacement with the bromide ionproduced by the in situ generation of HBr. This step is novel in thatthis is the first time that a primary alcohol (having a molecualr weightgreater than n-butanol) has been converted in high yield to a primarybromide using a sodium bromide/sulfuric acid process. Further, thein-situ formation of the HBr reagent significantly simplifies thereaction and the concomitant materials handling concerns of such astrong acid were it not so produced. Unexpectedly, the bromination ofthe TME tri-acetate only produces the TME dibromoacetate. Surprisingly,formation of the mono-bromo and tri-bromo TME derivatives is notobserved. ##STR1##

In the second step, see Formula 2 below, the oxetane ring is closed byreacting the TME dibromoacetate with NaOH in refluxing CCL₄ (or n-butylchloride) using a quaternary ammonium salt as a phase transfer catalyst(PTC). The ratio of the PTC to the TME dibromoacetate may range from 0.1to about 2.0% wt/wt and is preferably 0.5% wt/wt. Upon reflux, the TMEdibromo derivative 3 closes to produce the 3-bromomethyl-3-methyloxetane4. Reaction temperature is dependent upon the reflux temperature and mayrange from room temperature to about 100° C., preferably from about 70°to about 80° C. An unexpected result of these reaction scheme is theabsence of by-products from competing reactions. ##STR2##

This phase transfer catalyzed intramolecular cyclization has not beenattempted before for the production of BrMMO. Prior attempts haveresulted in low yields of the cyclic products (12-60%) due to twoprinciple side reactions. The first side reaction is the formation of astable olefin, 3-bromo-2-methylprop-1-ene, in preference to therelatively more strained oxetane ring. A second competing reaction isthe formation of the dimer and trimer.

These side reactions are minimized by choosing an appropriate solvent.We have found that n-butyl chloride and carbon tetrachloride providedyields of BrMMO on the order of 94-97%. Other solvents investigated,such as toluene, ligroine, 1,1,2-trichloroethane, benzene, n-hexane andhexanes gave more complex reaction mixtures containing both competingside reactions of elimination and dimerization.

BrMMO can easily be converted to a large variety of asymmetricallysubstituted oxetanes via displacement of the primary bromide, anexcellent leaving group. These monomers can then be polymerized viaLewis acids to provide polymers with a wide range of applications inenergetic and coating materials. Examples of synthesized and possiblemonomers are listed below. ##STR3##

The ability to produce these monomers is dependent upon the clean, highyield process for the formation of BrMMO without the competing sidereactions and associated by-products normally associated with this typeof reaction. This is due to the unexpected effect of the phase transferreaction of a base catalyzed internal cyclization of the TME dibromoderivative 3 of Formula 2.

While this discussion has been directed to the synthesis process ofBrMMO, the reaction conditions described above can be used to produce a3-bromomethyl-3-ethyl oxetane using 1,1,1-trimethylol propane ("TMP") asthe starting material. Also, this process can be used for the synthesisof other mono-haloalkyl oxetanes such as 3-chloromethyl-3-methyloxetane,3-iodomethyl-3-methyloxetane, 3-chloromethyl-3-ethyloxetane, etc.

OXETANE MONOMERS

The BrMMO of this invention may be further processed for the preparationof mono-substituted FOX monomers and prepolymers derived from thehomo-polymerization and copolymerization of the FOX monomers.

The incorporation of fluorine in a polymer alters the properties of theresulting polymer:

1. Thermal stability increases thus extending the upper use temperatureof the polymer and allows these materials to be processed at highertemperatures without degradation making them suitable for use inenvironments where other hydrocarbon based polymers cannot be used.

2. Surface energy decreases thus improving the release characteristicsof the polymer making it suitable for use as backings for adhesivetapes, release coatings for molds, fouling release coatings for shiphulls, and the like.

3. Refractive index of the resulting polymer is reduced making it usefulfor optical applications such as contact lenses, intraocular lenses,coatings for optical instruments, cladding for optical fibers, and thelike.

4. Coefficient of friction is reduced thus improving the lubricity ofthe coating making it useful in applications such as vehicle seals,windshield wipers, drag reducing coatings for sail boats, airplanes,etc.

5. Hydrophobicity increases, thus improving water repellency andmoisture barrier characteristics making the polymer useful forencapsulating electronic devices, moisture barrier films and coatings,rain erosion coatings, anti-corrosion coatings, etc.

6. Oleophobicity increases, thus making the polymer oil repellent anduseful as a stain resistant coating for garments and carpets.

7. Flammability decreases, thus improving flame retardency, for example,on garments coated with the polymer.

8. Environmental stability of the polymer improves, thus making thepolymer more stable when exposed to ultraviolet light and moisture.

The mono-substituted fluorinated alkyloxy-3-methyloxetane monomers ofthis invention have the following formula: ##STR4## Where: n is 1 to 3,

R is methyl or ethyl, and

R_(f) is a linear or branched chain fluorinated alkyl and isoalkylhaving from 1 to 20 carbons, or an oxa-perfluorinated polyether havingfrom 4 to about 60 carbons.

The FOX monomers of this invention are obtained by reaction of arylsulfonate derivatives of 3-hydroxymethyl-3-methyloxetanes(arylsulfonate-MO) or the reaction of mono-substituted3-haloalkyl-3-methyloxetanes with fluorinated alkoxides in the presenceof a polar aprotic solvent: ##STR5## where: R_(f) is linear or branchedchain perfluorinated alkyl or isoalkyl having from 1 to 20 carbons, oran oxa-perfluorinated polyether having from 4 to about 60 carbons; and

X=Br, Cl, I or an aryl sulfonate.

Note that the numeric FOX designation is determined by the number offluorine atoms in the terminal perfluoroalkyl group of the side-chain.

The aryl sulfonate derivatives of the hydroxyalkyl oxetanes have thegeneral formula: ##STR6## Where: R_(a) is monocyclic aryl having from

C₆ to C₁₀ carbons, e.g., benzyl, tolyl, x-ylyl, mesityl or an alkyl suchas --CH₃ or --CF₃.

The preferred sulfonates are toluene sulfonates, e.g., p-toluenesulfonate derivatives of 3-hydroxymethyl-3-methyloxetane (HMMO).

The fluorinated alkoxides are obtained by the reaction of fluorinatedalcohols with sodium hydride in a suitable solvent such asdimethylformamide:

    R.sub.f (CH.sub.2).sub.n OH+NaH R.sub.f (CH.sub.2).sub.n O.sup.- Na.sup.+ +H.sub.2

Although sodium hydride is the preferred base for this reaction, otherbases such as potassium hydride, potassium t-butoxide, calcium hydride,sodium hydroxide, potassium hydroxide, NaNH₂, n-butyl lithium andlithium diisopropylamide may be used.

The fluorinated alcohols which can be used have the general formula:

    R.sub.f (CH.sub.2).sub.n OH

wherein:

n is 1 to 3; and

R_(f) is a linear or branched chain fluorinated alkyl or isoalkyl havingfrom 1 to 20 carbons, or an oxa-perfluorinated polyether having from 4to about 60 carbons.

Examples of suitable fluorinated alcohols are: trifluoroethanol,heptafluorobutanol, pentadecafluorooctanol, tridecafluorooctanol, andthe like. Other useful alcohols include fluorinated alcohols having thefollowing formulas: ##STR7## wherein n is 1 to about 3 and x is 1 toabout 20.

Whereas the preferred solvent for the formation of the alkoxide fromthese alcohols is dimethylformamide (DMF), other solvents such asdimethylacetamide, DMSO and hexamethylene phosphoramide (HMPA) may beused.

The pre-monomer of this invention, BrMMO, is particularly well suitedfor the Synthesis of the oxetane monomers in that the BrMMO is uniquelyclean and free of by-products resulting from its novel syntheticpathway.

The displacement reaction can be conducted at temperatures ranging from25° C.-150° C., however, the preferred temperature is between 75° C. and85° C. At lower temperatures, the rate of displacement may be consideredslow and marginally useful for commercial scale-up. At highertemperatures (>120° C.), the rate of displacement is extremely fast.However, at these higher temperatures other side reactions such ashydrolysis of the premonomer to 3-hydroxymethyl-3-methyloxetanedominate. Thus, the preferred reaction temperature is <120° C.

Preferred Process for Synthesis of FOX Monomers

We have recently discovered a preferred process for preparing FOXmonomers in high yields that eliminates the use of organic solvents andstrong bases, such as NaH. The elimination of organic solvents reduceshazardous waste generation and air emissions of volatile organiccompounds. The process steps are as follows: ##STR8## where: R_(f) islinear or branched chain perfluorinated alkyl or isoalkyl having from 1to 20 carbons, or an oxa-perfluorinated polyether having from 4 to about60 carbons; and

X=Br, Cl or I.

In this process, a mixture of 3-haloalky-3-methyloxetane, fluoroalcohol,a base such as sodium hydroxide or potassium hydroxide, and a phasetransfer catalyst is heated in an aqueous medium at 80°-85° C. until GLCanalysis reveals complete consumption of the starting materials. Uponcompletion of the reaction, the product is recovered by separation anddistillation of the organic phase. The organic phase contains most ofthe FOX monomer. The recovered FOX monomer is polymer grade and has apurity normally in excess of 99%. Isolated yields are high and rangefrom 80% to 90% for the purified FOX monomer. Yields prior to separationand purification exceed 90% for the crude product.

Although a variety of bases such as calcium hydroxide, magnesiumhydroxide, tetrabutylammonium hydroxide, etc. can be used for thisprocess, the preferred bases are sodium hydroxide and potassiumhydroxide as they are readily available in large quantities and arerelatively inexpensive.

Phase transfer catalysts function by transferring the counterion so thatit is more soluble in the organic phase. A variety of phase transfercatalysts can be used for this process, such as tetramethylammoniumbromide, tetraethylammonium bromide, tetramethylammonium iodide,cetyltributylammonium bromide, crown ethers, glycols, and the like. Thepreferred catalyst is tetrabutylammonium bromide due to its relativelylow cost and good solubility in both organic and aqueous mediums.

The above reaction can be conducted at temperatures as low as 50° C. andas high as 120° C. However, at low temperatures, the rate ofdisplacement is extremely slow and competing side reactions such ashydrolysis start to dominate. At higher temperatures, the rate ofdisplacement is extremely fast requiring specialized equipment that canhandle pressure, thus making the process uneconomical and unattractivefor commercial scale-up.

The above preferred phase transfer catalyst process is limited to the3-haloalkyl-3-methyloxetanes and, therefore, precludes using thearylsulfonate derivatives of the 3-hydroxymethyl-3-methyloxetane asstarting materials for the synthesis of FOX monomers. This is becausearylsulfonates are sensitive towards hydrolysis and under the abovephase transfer conditions, hydrolyze readily to form3-hydroxymethyl-3-methyloxetane, thus resulting in lower yields. Thislimitation is overcome, however, by the process of this invention whichprovides high purity 3-bromomethyl-3-methyloxetane in high yields.

2. Prepolymers

There are three types of prepolymers of this invention: Homo-prepolymerswhere the prepolymer is assembled from only one FOX monomer;Co-prepolymers where the prepolymer is assembled from a mixture of FOXmonomers; and FOX/THF co-prepolymers where a FOX monomer (or mixture ofFOX monomers) is copolymerized with tetrahydrofuran (THF).

One of the main applications of the hydroxy-terminated, FOX prepolymersis in the development of hydrophobic, non-stick, low friction materials.The most important criteria in preparation of these materials is theminimization of the surface energy, which is a measure of thewettability of the material and defines critical properties such as itshydrophobicity and adhesive characteristics.

In order to prepare materials with low surface energies, it is criticalthat the fluoroalkyl group is present in the side-chain and that theterminal carbon of the fluoroalkyl group is perfluorinated. Therequirement to have fluorine in the side-chain rather than in thepolymer backbone is demonstrated by comparing the surface energies offluorinated polyacrylates and polytetrafluoroethylene (Teflon). Surfaceenergy of Teflon, which contains fluorine in the polymer backbone, is18.5 ergs/cm². By comparison, the surface energy of polyfluoroacrylates,which contains fluorine in the side-chains, is between 10-12 ergs/cm²Also, fluoroalkyl groups that contain hydrogen or halogen (Cl, Br, I) onthe terminal carbon have considerably higher surface energies than thosewith CF₃ groups. The dependence of surface energy on the surfaceconstitution of typical organic materials is shown in Table 1.

                  TABLE 1                                                         ______________________________________                                        SURFACE ENERGIES OF ORGANIC MATERIALS                                         SURFACE CONSTITUTION                                                                            ERGS/CM.sup.2 @ 20° C.                               ______________________________________                                        --CF.sub.3 Close Packed                                                                          6                                                          --CF.sub.2 H      15                                                          --CF.sub.2 --     18                                                          --CH.sub.3        22                                                          --CH.sub.2 --     31                                                          --CH.sub.2 CHCl-- 39                                                          Polyester         43                                                          ______________________________________                                    

It is also preferred to use oxetane monomers substituted at the3-position With only one perfluoroalkyl group since polymerization of3,3'-disubstituted oxetane monomers yield prepolymers that are largelycrystalline which foreclose preparation of elastomers having therequired preoperties. For example, polymerization of3,3'-bis(chloromethyl)oxetane yields a crystalline polymer that melts atapproximately 220° C. Similarly, polymerization of3,3'-bis(ethoxymethyl)oxetane provides a prepolymer that melts atapproximately 80° C.

It should be noted that crystalline prepolymers can not be used in thepreparation of polyurethane elastomers. Also, prepolymers fromdisubstituted FOX monomers contain large amounts of nonfunctional cyclicoligomers, which degrade polymer properties. Surface properties aredependent on the amount of fluorine at the polymer/air interface, and inthe case of FOX prepolymers, excellent enrichment of the polymer surfacewith fluorine is achieved and yet with only one perfluoroalkyl group.Surprisingly, we have discovered that a second fluorinated side chaindoes not significantly enhance the surface properties, and thus, itsintroduction in the prepolymer is both not cost effective and foreclosesthe the fluorinated elastomer field since it introduces crystallinesymmetry properties.

We have discovered and recognized that placing the fluorine in theside-chain, rather than on the backbone as in Teflon, improves surfacelubricity, and the resulting prepolymer/elastomer exhibits a surfaceenergy lower than a polymer having fluorine in just the backbone. Wehave discovered, however, that there is a trade-off between having thefluorine on the side-chain versus on the backbone: While we getincreased lubricity by incorporating a fluorinated side-chain, there isa reduced thermal stability as compared to a polymer having fluorineonly on the backbone, for example Teflon.

Hydroxy Terminated Homo- and Co-prepolygers

The invention also comprises the process of polymerizing FOX monomers,as well as the resultant hydroxy-terminated prepolymers. Theseprepolymers have the following formula: ##STR9## wherein: n is 1 to 3;

R is methyl or ethyl;

R₁ is H or a terminal alkyl alcohol residue having from about 2 to about5 carbons;

R_(f) is a linear or branched chain fluorinated alkyl or isoalkyl havingfrom 1 to 20 carbons, or an oxa-perfluorinated polyether having from 4to about 60 carbons; and

x is 10 to about 250.

The method of making the FOX homo- and co-prepolymers includes the stepsof:

1) charging a reactor with a catalyst, an initiator and a solvent;

2) adding a solution of FOX monomer(s) in an appropriate organic solventat a temperature between -20° C. and +60° C.;

3) reacting the FOX monomer(s) with the catalyst/initiator solution;

4) quenching the reaction; and

5) separating the FOX prepolymer by precipitation in methanol.

The polymerization can be homopolymerization or copolymerization inwhich a mixture of two or more of the afore-described oxetane monomersis added to the polymerization zone. A particularly usefulCopolymerization is block polymerization in which the comonomers aresequentially added in selected proportions to obtain block copolymers ofcontrolled block sizes and properties.

Solution polymerization of the invention may be conducted at a solidsconcentration of 5%-85%, however the preferred polymerization isnormally conducted at a concentration of 50-60% solids. Thepolymerization is conducted in the presence of a suitable inert solvent,preferably a halogenated C₁ to C₅ hydrocarbon, e.g., methylene chloride,carbon tetrachloride, chloroform, trichloroethylene, chlorobenzene,ethyl bromide, dichloroethane, fluorinated solvents, etc. and mixturesthereof, with the preferred solvent being methylene chloride, or amixture of methylene chloride and Freon. Other solvents such as sulfurdioxide, hexanes, petroleum ether, toluene, dioxane and xylene can alsobe used.

The FOX monomers readily polymerize in the presence of a Lewis acidcatalyst (i.e., compounds capable of accepting a pair of electrons) anda polyhydroxy aliphatic compound as a polymerization initiator. SuitableLewis acids for use as catalysts include: complexes of borontrifluoride, (e.g., BF₃.etherate and BF₃.THF phosphorus pentafluoride,antimony pentafluoride, zinc chloride, aluminum bromide, and the likeand mixtures thereof. The preferred Lewis acid catalyst is a BF₃.THFcomplex.

Suitable initiators are polyhydroxy aliphatic compounds such as alkyland isoalkyl polyols having from 2 to about 5 carbons and from 2 to 4hydroxyls, e.g., ethylene glycol, butane-1,4-diol, propylene glycol,isobutane-1,3-diol, pentane-1,5-diol, pentaerythritol,trimethylolpropane, and the like, and mixtures thereof, with thepreferred initiator being butane-1,4-diol.

The catalyst and initiator are preferably mixed for 5-10 minutes in thesolvent prior to the addition of the FOX monomers. The ratio of catalystto initiator ranges from 1:1 to 1:5 mol/mol with the preferred ratiobeing 1:1 to 1:2 mol/mol. An example of a preferred catalyst, initiatorand solvent combination is boron trifluoride tetrahydrofuranate,butane-1,4-diol and methylene chloride. The ratio of the monomer to thecatalyst ranges from about 10:1 mol/mol to about 300:1 mol/mol, with thepreferred range about 50:1 to 100:1 mol/mol.

In a typical example, the catalyst and the initiator are mixed in asolvent prior to the addition of the FOX monomer(s). As oxetane monomerspossess relatively high strain energy and undergo exothermic,ring-opening polymerizations, the FOX monomer(s) is added slowly over aperiod of time to-control the reaction temperature and to avoid run-awayreactions. The progress of the reaction is monitored by ¹ H NMR andwhen >95% of FOX monomer is consumed, the reaction is quenched withwater. The prepolymer is purified by precipitation in methanol.

The molecular weight of the prepolymer can be controlled by varying themonomer/catalyst ratio and the reaction temperature. Generally, lowermonomer/catalyst ratios and higher reaction temperatures favor theformation of lower molecular weight prepolymers. The ratio of monomer tocatalyst can be from 10:1 to 300:1, however, the ratios commonly usedrange from 50:1 to 100:1 monomer/catalyst.

The reaction temperature can be varied from -20° C. to +60° C., however,the preferred reaction temperature is +5° C. At higher temperatures,formation of monofunctional materials, mainly --CH₂ F terminatedmaterials, is Observed. Mono-functional materials can act as chainterminators, thus limiting the molecular weight of the final polymer aswell as increasing the polydispersivity. This , in turn, results inpolymers having poor mechanical and physical properties.

Cyclic oligomers are normally formed as by-products in the synthesis ofpolyether prepolymers. These materials are non-functional and reduce theusefulness of the prepolymers. Moreover, these materials can leach outof the polymer matrix, and thereby drastically affect the surface andmechanical properties of the polymer. Prepolymers prepared byhomopolymerization of FOX monomers contain approximately 2-7% cyclictetramer.

The BF₃ -etherate catalyst results in approximately 10%-15% of themono-functional material and approximately 6%-7% cyclic tetramerby-product.

The preferred catalyst is BF₃.THF which results in less than 2% of thecyclic tetramer byproduct and eliminates the formation of themono-functional prepolymer. In turn, this increases the functionality ofthe prepolymer and leads to polymers having excellent mechanical,surface and physical properties.

The polymerization of FOX monomers occurs by cationic ring-openingreaction. The mechanism for which is presented in FIG. 2.

The polymerization is initiated by the proton donated by the initiator,and the protonated oxetane ring undergoes propagation with otheroxetanes to generate the polymer chain. The growing poller chain is thenterminated either with alcohol or water to give hydroxy-terminatedpolyether prepolymers of this invention. It should be noted that theprepolymers of this invention are mixtures of prepolymers resulting fromboth alcohol and water terminations.

We have discovered through NMR analysis (¹ H/¹³ C) of the prepolymerthat the initiator fragment, in particular the butanediol fragment, islocated at the end of the polymer chain, and is not incorporated in themiddle of the prepolymer backbone. The NMR data (¹ H/¹³ C) clearly showsthe presence of a --CH₂ CH₂ CH₂ CH₂ OH group which can only occur if thebutanediol fragment is present at the end of the prepolymer chain. Ifthe butanediol fragment was incorporated in the middle of theprepolymer, we would see only two peaks corresponding to the symmetrical--OCH₂ CH₂ --CH₂ CH₂ O-- group. Our NMR data does not show the presenceof this group. While in theory the initiator fragment may beincorporated in the middle of the prepolymer, it is highly unlikely thatthe bulky, high molecular weight prepolymer will compete efficiently asa chain terminator with a low molecular weight, highly mobilebutanediol. The result of the polymerization with the diol initiator isa prepolymer with an unsymmetrical butanediol fraction at the end of theprepolymer chain. Our work is consistent with Conjeevaram et al. (J. ofPolymer Science, Vol. 23, 429-444 (1985)) in which 1,4-butanediol isused as an initiator in conjunction with a BF₃.etherate to polymerizeun-substituted oxetanes. His ¹³ C NMR analysis also revealsincorporation of the butanediol fragment as the unsymmetrical group--CH₂ CH₂ CH₂ CH₂ OH at the end of the polymer chain.

The prepolymers of this invention are amorphous, low Viscosity oils thatare easy to process. The inherent viscosity of the prepolymers arebetween 0.05 and 0.08 dL/g. The number average molecular weights of theprepolymers as determined by gel permeation Chromatography, are between1,000 and 30,000. The polydispersivity, a measure of the spread or "Q"of the molecular distribution, is very low, on the order of less than 5and typically between 1.1-2.0. The prepolymers exhibited unimodalmolecular weight distribution, and were contaminated with approximately2-7% cyclic tetramer.

It should be noted that molecular weights reported in this invention areexpressed relative to well characterized polystyrene standards. Theequivalent weight of the prepolymers was determinated by ¹ H NMRemploying TFAA end group analysis and were between 2,500 and 9,000. Theglass transition temperature of the prepolymers, as determined by DSCanalysis, was between -38° C. and -45° C.

The structural analysis of the homo- and co-prepolymers of thisinvention was conducted with ¹ H, ¹³ C and ¹⁹ F NMR spectroscopy. ¹ HNMR analysis revealed the presence of a trimethyleneoxide-basedpolyether backbone. ¹ H NMR analysis also indicated that whenBF₃.etherate is used as a catalyst, substantial amounts ofmono-functional material with --CH₂ F and --OCH₂ CH₃ end-groups isformed. However, when BF3.THF is used as a catalyst, formation ofmono-functional material is not observed. ¹ H NMR was also used toestablish the ratio of the two monomers in the co-prepolymer and theidentity of the end groups. ¹⁹ F NMR analysis confirmed the presence offluoroalkyl side-chains and the absence of materials with --CH₂ F endgroups and impurities such as Freon, HF and BF₃ catalyst.

¹³ C NMR analysis of the co-prepolymers such as poly 3/7-FOX and poly3/15-FOX, revealed that these materials are random copolymers withlittle, if any, block structure.

The prepolymers described above are oils that can be used as lubricantsor as additives for a variety of applications. For example, thesematerials can be used as additives in cosmetics to impart waterrepellency and release characteristics. Also, these materials can beused as additives in engine oils to reduce engine wear and improveperformance. The principal application, however, is in the preparationof fluorinated polymers which in turn can be used for diverseapplications ranging from car wax to materials for medical and dentalapplications such as prosthetics and catheter linings.

Co-Prepolymers with Tetrahydrofuran

We have discovered that the fluorinated oxetanes of this invention maybe co-polymerized with THF to provide a FOX/THF co-prepolymer havingvery unique, unexpected characteristics. These are a new class offluorine containing, hydroxy-terminated, polyether prepolymers, whichwhen cured with polyisocyanates, provide tough polyurethane elastomersthat are characterized by low glass transition temperatures and lowsurface energies. Moreover, these elastomers can be incorporated intocoatings that exhibit high abrasion resistance and low coefficient offriction. Combinations of these properties make polymers derived fromthese fluorinated co-prepolymers extremely attractive for a variety ofapplications including, but not limited to, anti-fouling (release)coatings; ice release coatings; corrosion resistant coatings, automotivetop coats (e.g., car wax), windshield wipers; belt strips; and varioushousehold goods; seals and gaskets; encapsulants for electronic devices;oil and dirt resistance coatings; and numerous medical/dentalapplications.

Tetrahydrofuran (THF) is a five membered cylic ether that iscommercially available and is known to polymerize or copolymerize withcationic catalysts but not with anionic catalysts. Attempts tocopolymerize THF with cyclic ethers, in particular, oxetanes isunpredictable. Polymerization occurs but the products are often notrandom copolymers. Due to the vast differences in ring-openingpolymerizability between THF and oxetanes, it is more likely that theproduct is a block copolymer rather than a random copolymer. Poly THF(PTHF) is a semi-crystalline polymer that melts at ca. 50° C., and whenemployed as the soft segment in urethane elastomers, is likely tocrystallize at low temperatures, causing problems with physicalproperties such as poor flexibility, incomplete or little recovery afterelongation, poor modulus, and the like. In a block, or non-random,copolymer, similar problems can occur since THF blocks can crystallizeand form semi-crystalline polymers.

In the FOX/THF random coprepolymer of this invention, THF and oxetanesegments are randomly spaced along the polymer backbone, thus leading toproducts that are amorphous oils. The random nature of ourco-prepolymers prevents backbone tacticity or any other form ofregularity that lends itself to ordering and the development ofcrystallinity. Hydroxy-terminated polyether prepolymers that are low incrystallinity, preferably amorphous, are particularly suitable as thesoft segments for urethane elastomers.

In this invention we describe the copolymerization of FOX monomers withtetrahydrofuran to give FOX/THF coprepolymers. Copolymerization of FOXmonomers with THF, not only reduces the cost of fluorinated prepolymersby using less of the relatively more expensive FOX monomers, but alsoprovides prepolymers with superior properties. The co-prepolymers ofthis invention are random copolymers and are ideal as soft segments forurethane elastomers. Moreover, these FOX/THF coprepolymers are amorphousoils that are easy to process. Also, the use of THF as a coreactantallows the polymerization to be conducted in bulk and eliminates the useof ozone depleting solvents such as Freons.

The FOX co-prepolymer composition has the following general structure:##STR10## where: n is 1-3;

R is methyl or ethyl;

R_(f) is a linear or branched perfluorinated alkyl group having 1-20carbons, or an oxaperfluorinated polyether having from about 4-20carbons;

X is 1-100 and Y is 10-150; and

R¹ is H or an alkyl alcohol residue having from about 2 to 5 carbons.

and:

M_(n) is 2,000 to 50,000; and

T_(g) is approximately -40° to -42° C.

Unexpectedly, the resulting coprepolymer sequence of this invention israndom. The random sequence of the coprepolymer, together with thepresence of the assymetric FOX segment, results in a low viscosity oilwhich significantly facilitates processing and the commercialapplication of the product.

The surface energy of the FOX/THF coprepolymer as a cured polymer islower than that of polytetrafluoroethylene (Teflon) and is attributed tothe presence of the fluorine in the side-chains rather than thebackbone. It is noteworthy that the FOX/THF prepolymer is formed fromthe mono-substituted FOX monomers of this invention and the surfaceenergy is comparable to that of the polymers formed from thebis-substituted monomers described in the background. Consequently, theFOX monomer is preferable to the bis-perfluoroalkyl monomers of thebackground, not only because the mono-substituted FOX monomers produceproducts having comparable or better surface energy, but also because ofits ability to copolymerize with THF, thus reducing the startingmaterials cost. Even though we have significantly reduced the amount offluorine in the FOX/THF co-prepolymer by introduction of the THFsegments, it has thus far been determined that when the FOX/THFcopolymer contains up to about 65% THF, no significant reduction insurface energy is observed in polyurethane elastomers as compared to theelastomers prepared from the mono-substituted FOX monomers.

The random nature of the co-prepolymer sequence is wholly unexpected andis achieved with the novel reaction conditions outlined below. Therandomness results in an amorphous, low viscosity oil. The benefits of aliquid prepolymer over a crystalline prepolymer (as would be expectedfor a block copolymer or a prepolymer produced from a bis-substitutedmonomer) include easier processing and mixing with reactants (e.g.,diisocyantes, cross-linkers, chain extenders, etc.).

The method of making the co-prepolymer includes the steps of:

1) premixing THF in an appropriate organic solvent, said THF and solventtemperature between -20° C. and +60° C.;

2) adding a catalyst;

3) adding an initiator;

4) adding a FOX monomer(s); said FOX monomer(s) temperature between -20°C. and +60° C.;

5) quenching the reaction; and

6) separating the FOX/THF prepolymer by precipitation in methanol.

Alternately, where the copolymer ratio of FOX to THF is between therange of 60:40 and 35:65, no organic solvent is required and theprepolymer may be made by addition of FOX to neat THF. The absence ofsolvent offers significant advantages to manufacturers with respect tothe environmental costs associated with solvent hazardous wastes andhazardous materials storage and handling, as well as the lowermanufacturing costs and enhanced public perception (i.e., a "green"product). Further, the presence of the hydrocarbon segment (the THFsegment), improves solubility of the co-prepolymer in hydrocarbons.

The copolymerization is conducted either in an inert solvent likemethylene chloride or Freon 113 or mixtures thereof, or in neat THF. The90:10 7-FOX/THF co-prepolymer is prepared in a 3:1 mixture of methylenechloride and Freon 113, whereas the 60:40 and 35:65 7-FOX/THFco-prepolymers are prepared in neat THF. Similarly, 50:50 13-FOX/THF and60:40 15-FOX/THF co-prepolymers are prepared in neat THF. In thesynthesis of 90:10 7-FOX/THF co-prepolymer, solvent is used to avoidviscosity build-up during polymerization, and can potentially beeliminated by using high torque mixers. Solution polymerization may beconducted at a solids concentration of 5%-85%, however, polymerizationis normally conducted at a concentration of 50-60% solids. Othersolvents that can be used for this process are carbon tetrachloride,chloroform, trichloroethylene, chlorobenzene, ethyl bromide,dichloroethane, fluorinated solvents, sulfur dioxide, hexanes, petroleumether, toluene, dioxane, xylene, etc. with the preferred solvent beingmethylene chloride, or a mixture of methylene chloride and Freon. Thefact that FOX/THF copolymers can be prepared in the absence of a solventis beneficial in the view of full scale production, since environmentalregulations highly restrict the emission of solvents, speciallyhalogenated solvents, into the atmosphere.

The catalyst and the initiator are similar to those used in thehomo-polymerization of FOX monomers. Suitable catalysts are Lewis acidsi.e., compounds capable of accepting a pair of electrons, example ofwhich include: complexes of boron trifluoride, phosphorouspentafluoride, SnCl₄, antimony pentafluoride, etc. Suitable initiatorsare water and aliphatic alcohols containing 2 to 5 carbons and 1 to 4hydroxy groups, e.g., trifluoroethanol, methanol, 1,4-butanediol,trimethylolpropane, pentaerythitol, etc.

In a typical example, the catalyst and the initiator are mixed in asolvent prior to the addition of the monomer. THF is a five memberedcyclic ether with low strain energy, and does not homopolymerize underthe reaction conditions. Thus, THF is added in one shot to the reactionmixture. On the other hand, oxetane monomers possess relatively highstrain energy and undergo exothermic, ring-opening polymerizations. Thus, FOX monomers are added slowly over a period of time to control thereaction temperature and to avoid run-away reactions. The progress ofthe reaction is monitored by ¹ H NMR and when >95% of FOX monomer isconsumed, the reaction is quenched with water. The prepolymer ispurified by precipitation in methanol.

The molecular weight of the co-prepolymer can be controlled by varyingthe monomer/catalyst ratio and the reaction temperature. Generally,lower monomer/catalyst ratios and higher reaction temperatures favor theformation of lower molecular weight co-prepolymers. The ratio of monomerto catalyst can be from 10:1 to 300;1, however, the ratios commonly usedare 100:1 monomer/catalyst. The temperature can be from -20° C. to +60°C., however, the preferred reaction temperature is +5° C. At highertemperatures, formation of monofunctional materials, mainly --CH₂ Fterminated materials, is observed. The +5° C. mean reaction temperatureeliminates the formation of --CH₂ F terminal groups which are unreactiveand would otherwise reduce the functionality of the prepolymer (byformation of the mono-functional product) and lead to polyurethanes withpoor mechanical properties.

In contrast to the FOX homo- and co-prepolymers, the formation of cyclicoligomers is not observed in the copolymerization of 7-FOX with >10%mole THF. Similarly, formation of cyclic oligomers is not observed inthe preparation of 50:50 13-FOX/THF and 60:40 15-FOX/THF co-prepolymers.A small amount of cyclic tetramer (ca. 1.0% ), however, is formed insynthesis of 90:10 FOX/THF co-prepolymer. It is postulated thatincorporation of THF in the growing polymer chain changes the number ofatoms in the polymer chain and does not allow the chain to bite back andform a thermodynamically stable, 16-membered cyclic ether. This resultis especially important in the development of non-toxic fouling releasecoatings, where discharge of any chemicals from candidate coatings isnot acceptable.

The FOX/THF co-prepolymers of this invention are amorphous, lowviscosity oils that are easy to process. FOX/THF co-prepolymers areslightly more viscous than FOX homo-prepolymers. The inherent viscosityof a 60:40 7-FOX THF co-prepolymer, determined in THF at 0.5 g/dLconcentration, is 0.125 dL/g. By comparison, the inherent viscosity ofthe 7-FOX homo-prepolymer is 0.072 dL/g. ¹ H NMR analysis of FOX/THFco-prepolymers indicates that both monomers are incorporated into theco-prepolymer, and that the THF segment is present in the middle of twoFOX segments, and not as an end group.

The ratio of the two monomers in the co-prepolymer is established bycomparing the area under the peaks corresponding to THF (ca. 1.6 ppm)and 7-FOX (0.93 ppm) segments. ¹ H NMR analysis also indicates thatFOX/THF copolymers are not contaminated with monofunctional materials(--CH₂ F terminated) or other impurities. Presence of multiple peaks inthe quartenary carbon region of ¹³ C NMR, corresponding to the carbonbearing the fluoroalkyl side-chain, reveal that the above prepolymersare random copolymers with little, if any, block structure. ¹⁹ F NMRanalysis confirm the presence of the fluoroalkyl side-chain and theabsence of --CH₂ F end groups, HF and BF₃ catalyst. It is important tonote that these materials are not block copolymers, since THF blockscould crystallize and lead to materials with increased crystallinity andpoor flexibility. This, in turn, would limit the usefulness of FOX/THFmaterials.

The number average molecular weights of FOX/THF co-prepolymers, asdetermined by GPC, were between 10,000 and 14,000, whereaspolydispersities were between 1.5 and 2.1. The co-prepolymers exhibitedunimodal molecular weight distribution, and with the exception of 90:107-FOX/THF co-prepolymer, FOX/THF co-prepolymers were free of cyclicoligomers. The equivalent weight of 60:40 7-FOX/THF co-prepolymer,determined by ¹ H NMR employing TFAA end group analysis, was 6,230. Theequivalent weight of the same co-prepolymer by p-toluenesulfonylisocyanate/dibutyl amine titration method was 5,890. The glasstransition temperature of the 60:40 7-FOX/THF co-prepolymer by DSCanalysis was -43° C., no other transitions were detected between -100°C. and +130° C. By comparison, the glass transition temperature of the7-FOX homo-prepolymer was -42° C. This result indicates that the glasstransition temperature of the co-prepolymer is not affected by theincorporation of THF. If the prepolymer was a block copolymer or amixture of two homopolymers, more than one transition would be observed.This was further confirmed by the dynamic mechanical propertymeasurements of 60:40 7-FOX/THF co-prepolymer where only one transition(T_(g)) was observed at -41° C. It should be noted that the formation ofa random copolymer between FOX and THF monomers is unexpected since thevast difference in the reactivity of these two monomers would dictatethe formation of a block copolymer or two homopolymers.

The co-prepolymers described above are oils that can be used aslubricants or as additives for a variety of applications. For example,the co-prepolymers can be used as additives to improve the performanceof commercial engine oils or as a lubricant for industrial equipment.The major use of FOX/THF co-prepolymers, however, is in the developmentof fluorinated polyether urethane elastomers.

3. Polymers

The hydroxy terminated prepolymers of this invention can be used for thesynthesis of a variety of polymers such as polyurethanes, polyesters,polycarbonates, polyacrylates, etc. Additionally, the FOX prepolymers ofthis invention may be used to synthesize novel fluorinated elastomers,thermosets and thermoplastics.

The fluorinated polyurethane elastomers of this invention exhibit thesurface properties of fluoropolymers, and the mechanical properties andthe processing characterisitics of traditional polyurethanes. Thesematerials exhibit low glass transition temperatures, low coefficient offriction, high abrasion resistance, and extremely low surface energies.In addition, these polymers exhibit excellent mechanical properties andcan be processed as thin coatings or into bulk articles. Alsofluorinated polyurethane-of this invention can be bonded to a variety ofsubstrates. Combination of these properties, make these materialsattractive for a variety of applications such as fouling releasecoatings for ship hulls and other marine structures; drag reducingcoatings for ship hulls and aircraft; moisture barrier coatings andencapsulants for electrical circuits; ice release coatings for aircraftand structures; anti-corrosion and protective coatings; coatings forautomotive top coats (e.g., car wax), gaskets and seals; backing foradhesive tape; windshield, eyeglass, and window coatings; binders forpropellants and flares; bushings for vibration damping; furniturepolish; non-transferable, water/oil proof cosmetics; water repellant forfabrics; oil/stain resistant coating for carpets; low friction coatingfor computer disks and magnetic head rails; and numerous medical/dentalapplications such as artificial hearts, artificial joints, catheters,contact lenses and intraoccular lenses.

Polyurethanes from FOX Homo-/Co- Prepolymers

The preparation of fluorinated polyurethane elastomers begin with theFOX prepolymers of this invention. As previously described, theseprepolymers are amorphous, low viscosity oils that are easy to process.Moreover, these materials are difunctional and possess terminal primaryhydroxy groups that react readily with isocyanates to form highmolecular weight polyurethane elastomers. Typically, the prepolymer isreacted with an equivalent amount of a polyisocyanate in the presence ofa catalyst and a crosslinking agent to form a three-dimensional, polymernetwork. The process involves mixing the components, casting them in amold, degassing, and curing the mixture at an elevated temperature.Alternately, the FOX prepolymer is reacted with excess diisocyanate andthe resulting isocyanate-capped prepolymer is reacted with thecrosslinking agent to form the thermoset. If desired, the isocyanatecapped-prepolymer can be reacted with a low molecular weight diol ordiamine (a chain extender) to form a linear, thermoplastic polyurethaneelastomer.

The fluorine-containing thermoset polyurethane elastomer of thisinvention is composed of repeat units, bounded by cross-linking agents,which have the following structure: ##STR11## where: n is 1-3;

R is methyl or ethyl;

R_(f) is a linear or branched perfluorinated alkyl group having 1-20carbons, or an oxaperfluorinated polyether having from about 4-20carbons

X is 10-200 and Y is 1-10

R¹ is an alkyl or aryl functional group, examples of which include thefollowing structures: ##STR12##

The resulting polyurethane is tack-free, opaque, generally insoluble inorganic solvents and has a glass transition temperature between -40° C.and -47° C. Contact angle measurements of between 110° and 145° withdistilled water and surface energy measurements of 13.8-15.2 ergs/cm²indicate that the surface wettability and non-adhesive characteristicsof the elastomer of this invention are greater than those measured forTeflon (110° contact angle and 18.5 ergs/cm² surface energy). We haveobserved that as the size of the side-chain on the FOX polymersincreases, hydrophobicity increases as well (see Table 3). As indicatedabove, the 145° contact angle of the polyurethane derived from the15-FOX prepolymer is characteristic of the extreme hydrophobicity of theFOX polymers of this invention. The 145° contact angle of the 15-FOXpolyurethane is one of the highest ever observed.

FIG. 1 shows the contact angle of a drop of doubly distilled water onthe 15-FOX polyurethane of this invention as compared to the contactangle of a doubly distilled drop of water on Teflon.

The polyurethanes of this invention exhibit the following novel set ofcharacteristics:

1) Elastomeric properties;

2) More hydrophobic and non-stick than Teflon;

3) Processable into thin coatings or bulk articles;

4) Flexible down to about -50° C.;

5) Bondable to a variety of substrates; and

6) Useful ambient temperature range from about -50° C. to about 240° C.

Glass transition temperature is the temperature at which the polymer istransformed from a brittle glass to a flexible elastomer. Thus, itdictates the lower use temperature of the elastomer. The glasstransition temperatures of non-plasticized FOX polyurethanes, asmeasured with a differential scanning calorimeter (DSC), are between-40° C. and -47° C. Normally, a plasticizer is used to impartflexibility and to lower the glass transition temperature of polymers.If desired fluorinated plasticizers such as Fomblin, Alfunox, and Kel-Foils can be used to improve the low temperature flexibility of FOXpolyurethane elastomers.

Contact angle is the obtuse angle of a water droplet on the polymersurface and reflects the wettability of the polymer surface. A waterdroplet does not spread on a hydrophobic surface and will exhibit a highcontact angle, indicating non-wetting characteristics of the polymersurface. The static contact angle of FOX polyurethanes with doublydistilled water were measured with a Goniometer, and were found to bebetween 110° and 145°. In sharp contrast, Teflon exhibits a contactangle of 110°. Surface energy is also an important measure ofwettability of the polymer surface and defines critical properties suchas its hydrophobicity and adhesive characterisitics. Materials with lowsurface energies are difficult to wet and thus exhibit excellent releasecharacteristics. Teflon, for example, exhibits a surface energy of 18.5ergs/cm², and is widely used in preparation of non-stick cookingutensils. Surface energies of common polymers are listed in Table 2. Thesurface energies of polyurethanes prepared from Poly 3/7 FOX (25:75) andPoly 7-FOX are 15.2 and 13.8 ergs/cm², respectively. These values areconsiderably lower than that of Teflon and other commercial polymers,indicating that FOX polyurethanes have superior release characterisiticsto Teflon. This makes the cured elastomer of this invention more suitedthan Teflon for those applications where lower wettability and enhancedreleased characteristics are desired in a coating material.

                  TABLE 2                                                         ______________________________________                                        SURFACE ENERGIES OF COMMERCIAL POLYMERS                                                        SURFACE ENERGY                                               MATERIAL         (ERGS/CM.sup.2)                                              ______________________________________                                        Teflon           18.5                                                         Polydimethylsiloxanes                                                                          24                                                           Polyethylene     31                                                           Polytrichlorofluoroethylene                                                                    31                                                           Polystyrene      33-35                                                        Poly(methyl-methacrylate)                                                                      33-34                                                        Nylon 66         46                                                           ______________________________________                                    

The method of making the polyurethane elastomer includes the steps of:

1) Premixing a FOX prepolymer with a polyisocyanate at a reagenttemperature between 25° C. and 100° C.;

2) Adding a catalyst;

3) Adding from about 0% to 15% wt/wt of a cross-linking agent;

4) Mixing the components;

5) Casting the components into a mold;

6) De-gassing the cast compound; and

7) Curing the compound mixture at a temperature of between 17° C. and150° C.

Normally, molar equivalent amounts of FOX prepolymer, cross-linkingagent and polyisocyanate are used. However, where the FOX prepolymer isadded to an excess of polyisocyanate, an isocyanate-capped prepolymer isproduced which may be further reacted With a cross-linking agent toproduce a thermoset polyurethane elastomer. Alternately, theisocyanate-capped prepolymer can be reacted with a low molecular weightchain extender such as a diol or diamine to prepare linear thermoplasticpolyurethane elastomers.

The crosslinking agents normally used are low molecular weight polyolsor polyamines such as trimethylolpropane, pentaerythitol, Isonol 93,trimethylolethane, triethanolamine, Jeffamines, 1,4-butanediamine,xylene diamine, diethylenetriamine, methylene dianiline, diethanolamine,etc. The preferred crosslinking agents are trimethylolpropane, Isonol93, methylene dianiline, and Jeffamines. The mechanical properties of anelastomer can be altered by varying the amount of crosslinking agent.Generally, increasing the amount of crosslinking agent in a polyurethaneformulation leads to materials with higher modulus and improved chemicaland abrasion resistance. The amount of crosslinking agent can be variedfrom 0-15% by weight, however, the preferred amount is between 1.5% and5% by weight.

The preferred catalyst is dibutyltin dilaurate, however, a variety ofcatalysts such as triethyl amine, triethylene diamine, triphenylbismuth, chromium acetylacetonate, lead octonate, ferricacetylacetonate, tin octanoate, etc, can also be used. It should benoted that the catalyst is added primarily to increase the rate of thereaction, and if desired the reaction can be conducted in the absence ofthe catalyst. The catalyst concentration can be between 0.001 to 1% bywt., however the preferred concentration is between 0.1% and 0.2% by wt.

The polyisocyanates useful in the synthesis of FOX polyurethanes are:hexamethylene diisocyanate (HDI), Isopherone diisocyanate (IPDI),Methylene diphenylisocyanate (MDI), saturated MDI (Des-W), polymeric MDI(Isonates), toulene diisocyanate (TDI), polymeric HDI (N-100 andN-3200), cyclohexylene-1,4-diisocyanate, and 2,2,4-trimethylhexmethylenediisocyanate. The NCO:OH ratio can be from 1.1 to 0.9, however thepreferred ratio is 1.02.

Bulk materials are prepared by casting the above formulation in a mold,degassing the mixture, and then curing it at 65° C. for 16 to 36 h. Athin film is prepared by diluting the above formulation with THF,spreading the mixture over the substrate with a Doctor's blade, and thencuring the coated substrate in an oven at 65° C. Alternately, thesubstrate can be dip-coated or spray coated and cured in an oven at 65°C.

The cure temperature can be between 20° C. to 150° C. The preferredtemperature is 65° C. The above formulation can be cured at roomtemperature by increasing the amount of catalyst to ca. 0.5%. The cureis also dependent on the thickness of the sample and type ofcrosslinking agent. Thin samples cure within 3 h at 65° C., whereas 1/8inch thick sample take between 8-16 h to cure. Also, amine-basedcrosslinking agents promote faster cures than polyols.

The mechanical properties of an unfilled elastomer are shown in Table 3.These properties indicate that polyurethanes prepared from FOXprepolymers are true elastomers (i.e., >100% recoverable elongation).

                  TABLE 3                                                         ______________________________________                                                                     Ten-                                                                          sile                                                                    Contact                                                                             Mod-            Water                            No.  Prepolymer % F    Angle ulus Strain                                                                              Stress                                                                             Abs.                             ______________________________________                                        1    Poly 3-FOX 31     110°                                                                         79     926%                                                                              670  --                               2    Poly 3/7-FOX                                                                             43     114°                                                                         34   1,256 427  0.22%                                 (25:75)                                                                  3    Poly 7-FOX 47     119°                                                                         41   1,308 622  0.16%                            4    Poly 3/15-FOX                                                                            52     128°                                                                         67   1,117 344  0.18%                                 (25:75)                                                                  5    Teflon     76     112°                                                                         --   --    --   --                               ______________________________________                                    

The effect of a filler on mechanical properties is demonstrated in Table4.

                  TABLE 4                                                         ______________________________________                                        FILLER          Contact MECHANICAL                                            No   Type       %       Angle T. Mod Strain                                                                              Stress                             ______________________________________                                        1*   --         0       114°                                                                         34 psi 1,256%                                                                              427 psi                            2    Teflon     5       --    41 psi 1,616%                                                                              556 psi                            3    Teflon     10      --    53 psi 1,294%                                                                              500 psi                            4    Teflon     20      --    73 psi 1,226%                                                                              425 psi                            5    Carbon Black                                                                             0.25    108°                                                                         42 psi 1,605%                                                                              444 psi                            ______________________________________                                         *Base polymer: Polyurethane from 25:75 Poly 3/7FOX                       

As expected, the tensile modulus increases and % elongation decreaseswith increasing filler loading. It is noteworthy that the use of a lowenergy filler like Teflon does not degrade the mechanical properties ofFOX polyurethane elastomers. This indicates that FOX polyurethanes willwet Teflon and thus allow Teflon to disperse, rather than agglomerate,in the filled polymer.

Surprisingly, FOX polyurethanes exhibit good adhesion to a variety ofsubstrates such as stainless steel, aluminum, graphite, EPDM rubber,glass and wood. In a typical process, the substrate is coated with thepolyurethane formulation, placed in an oven, and cured. Please note thatno special treatment or primer is required to bond fluorinatedpolyurethane to the substrate. Peel strength indicates the bondingcharacteristics of the coating to substrate and is measured with anInstron. Polyurethanes from hydroxy-terminated polybutadiene bondstrongly to EPDM substrates and exhibit peel strengths that are in theneighborhood of 9.5 lbs/in; the bond failure is cohesive. Thepolyurethane prepared from FOX-7 prepolymer, Isonol-93, and Des-Wexhibit a peel strength of 9.5 lbs/in and an adhesive bond failure. Thegood bonding characteristics of FOX polyurethanes is attributed to thepresence of polar urethane groups in the polymer backbone, which incontrast to fluoroalkyl groups, orient towards the high energy surface.A well adhering coating should, therefore, contain chemical groups thatwill contribute to enhance the polarity of the coating and bring it intothe range of the substrate. A system containing both dipole-dipole andhydrogen-bond contributions is preferred over a system containing onlyone such contribution because of its broader compatibility. Duringapplication, the system must be sufficiently fluid in order to encouragerapid spreading, uniform coating and good wetting. Since Teflon has thefluorine symmetrically bonded to the polymer backbone, there is nodipole or hydrogen bonding with which the polymer may bond to asubstrate surface. Consequently, a Teflon coating will not exhibit goodadhesion or peel strength with its underlying substrate.

Thermal stability of FOX polyurethanes was determined bythermogravimetric analysis (TGA). These materials exhibit 0% wt. loss inair to 260° C. and onset of major thermal degradation in air at 275° C.This study indicates that FOX polyurethanes should not be exposed totemperatures in excess of 250° C.

The above results indicate that the polyurethanes prepared from FOXprepolymers are more hydrophobic and non-stick than Teflon. In sharpcontrast to Teflon, FOX polyurethanes are tough elastomers that can beprocessed into thin coatings or into bulk articles. Moreover, thesematerials are flexible at low temperatures and can be used attemperatures as low as -50° C. Also, these materials can be bonded to avariety of substrates, and can be used between the temperature limits of-50° C. and 250° C. This invention provides novel materials that can bebonded strongly to a variety of substrates and at the same time providea surface that is more hydrophobic and non-stick than Teflon. Materialswith combinations of these properties are not known and thus FOXpolyurethanes fulfill an important niche in the market place forprocessable, low surface energy elastomers.

Polyurethanes From FOX/THF Co-prepolymers

FOX/THF co-prepolymers may be also used to produce polyurethaneelastomers with useful properties. Polyurethanes prepared from FOX/THFco-prepolymers exhibit better adhesion, higher abrasion resistance, andsuperior mechanical properties than those derived from FOXhomo-prepolymers. Moreover, the key properties of FOX polyurethanes arenot affected by incorporation of THF in the polymer structure. That is,polyurethanes prepared from FOX/THF co-prepolymers still exhibit lowglass transition temperature, low coefficient of friction, and lowsurface energy-properties that are similar to those of polyurethanesderived from FOX homo-prepolymers.

The FOX/THF co-prepolymers described in this invention are difunctionaland have terminal hydroxy groups. These hydroxy groups are primary andreact readily with isocyanates to form high molecular weightpolyurethane elastomers. In a typical reaction, the co-prepolymer isreacted with an equivalent amount of polyisocyanate in the presence of acatalyst and a crosslinking agent to form a 3-dimensional polymernetwork. If the functionality of the polyisocyanate is 2, then acrosslinking agent is needed to form a crosslinked network. However, ifthe functionality of the polyisocyanate is >2, then no crosslinkingagent is needed. In some cases, additional crosslinking agent is addedto improve the chemical and abrasion resistance of the polymer. Thecrosslinking agent normally used is a low molecular weight polyol orpolyamine such as trimethylolpropane, Isonol 93, Jeffamines,trimethylolethane, pentarerythitol, triethanol-amine, diethanolamine,4,4-methylene dianiline, MOCA, 1,4-butanediamine, diethylenetriamine,xylene diamine, etc. The preferred crosslinking agents are Isonol 93,trimethylolpropane and Jeffamines. The preferred catalyst is dibutyltindilaurate, however other catalysts such as triethylamine, DABCO, Ferricacetylacetonate, triphenyl bismuth, tin octanoate, lead octanoate, etc.,can also be used. The catalyst concentration is normally between 0.1 and0.2% by weight. The polyisocyanates useful in the synthesis offluorinated polyurethanes are hexamethylene diisocyanate (HDI),Isopherone diisocyanate (IPDI), 4,4-methylene diphenylisocyanate (MDI),polymeric MDI (Isonates), toluene diisocyanates, saturated MDI (HMDI),polymeric HDI (N-100 and N-3200), and trimethylhexane diisocyanate. TheNCO:OH ratio can be from 1.1 to 0.9, but the preferred ratio is 1.02.Bulk materials are prepared by casting the above formulation in a mold,degassing the mixture under reduced pressure for 15 mins, and thencuring it in an oven at 65° C. for 16 h. If a thin film is desired, asolvent, like THF, is added to reduce the viscosity, and the mixture isspread over the Substrate with a doctor's blade to form a film ofdesired thickness. Alternately, the substrate can be dip-coated or spraycoated, then cured in an oven at 60° C.-65° C.

Cure, that is the reaction of prepolymers with polyisocyanates andcrosslinking agents to form high molecular weight, crosslinked polymernetwork, is normally conducted at temperatures from 20° C. to 150° C.The preferred cure temperature is 65° C. The above formulations can becured at room temperature by increasing the amount of catalyst to 0.5%.Also, thin films cure faster than bulk materials. The cure time is alsodependent on the amount of the catalyst, temperature, and the type ofcrosslinking agent. Higher catalyst loading and higher temperature favorfaster cures. Also, amine-based cross-linking agents promote fastercures than polyols. A formulation containing FOX/THF co-prepolymer,Isonol-93, HMDI, and 0.2% wt. catalyst cures in ca. 7 h at 65° C. togive a tack free, 1/8 inch thick polyurethane elastomer. Under similarconditions, a 20 mil thick film will cure in 2 h at 65° C. When theabove cure is repeated with an amine crosslinking agent, the cure timeis reduced to <30 mins at 40° C.

In general, polyurethanes prepared from FOX/THF co-prepolymers aretack-free, opaque elastomers. They exhibit glass transition temperaturesbetween -41° C. and -46° C., and static contact angles with waterbetween 108° and 126°. These materials are insoluble in common organicsolvents like methanol, toluene, hexanes, carbon tetrachloride, methylethylketone and kerosene, but swell in THF and Freon 113. The mechanicalproperties of an unfilled elastomer, as measured with an Instron, fallwithin the following limits:

Tensile Modulus: 35 psi to 205 psi

Elongation at Break: 400% to 1624%

Tensile Strength: 380 psi to 624 psi

An elastomer that has been characterized in detail is prepared from60:40 7-FOX/THF co-prepolymer, Isonol 93 and HMDI, in the presence ofdibutyltin dilaurate catalyst. The candidate material, a 3×5×0.2 inch³sample, is an opaque elastomer. The static contact angle of thismaterial with doubly distilled water is 117°. By comparison, staticcontact angles of water with Teflon and 7-FOX polyurethane are 110° and119°, respectively. The surface energy of the candidate material, asdetermined by the method of Wu et al., is 13.5 erg/cm². This value isconsiderably lower than that of Teflon (18.5 ergs/cm²), but similar tothat of 7-FOX polyurethane (13.2 ergs/cm²). The above results indicatesthat polyurethane prepared from 7-FOX/THF co-prepolymer is comparable inrelease characteristics and hydrophobicity to 7-FOX polyurethane, but issubstantially more non-wettable and non-stick than Teflon. In view ofthe reduced amount of fluorinated starting materials required toassemble the mono-substituted FOX monomers of this invention and furtherin view of the reduced amount of FOX monomer required in order toassemble a FOX/THF co-prepolymer, there is a significant cost savingsover prepolymers assembled from the bis-substituted monomers orprepolymers assembled solely from the FOX monomers.

The candidate material exhibits a tensile modulus of 53 psi, elongationat break of 1624%, and a tensile strength of 624 psi. Recoverableelongation is in the neighborhood of 1200%. By comparison the mechanicalproperties of 7-FOX polyurethane are: tensile modulus=41 psi; elongationat break=1308%; and tensile strength=622 psi. This result isparticularly interesting since it indicates that copolymerization of7-FOX with THF improves both stress and strain capabilities of the 7-FOXpolyurethane elastomer. It should be noted that the mechanicalproperties can be tailored by varying factors such as, crosslinkdensity, type of isocyanate, amount of plasticizer, filler loading, %hard block, etc. The glass transition temperature of the elastomer, asmeasured with DSC, was -43° C., whereas by rheometric mechanicalspectrometer (RMS) it is -42° C.

The candidate material exhibits good to excellent adhesion to a varietyof substrates such as, stainless steel (SS 304), graphite, EPDM rubber,aluminum, and glass. Typically, the substrate is cleaned with water andacetone and then dried in an oven prior to use. Bonding is achieved bycuring the mixture of prepolymer, cross-linking agent, polyisocyanate,and the catalyst directly on the substrate.

In one experiment, EPDM substrate was coated with a 0.20 inch thick filmof the candidate material, and peel strength was measured with anInstron. The candidate material exhibited a peel strength of >10 lb/inwith a cohesive bond failure. The peel strength of 7-FOX/THFpolyurethane compares favorably with the peel strength of polyurethaneprepared from hydroxy-terminated polybutadiene, Isonol 93 and HMDI (>9.8lb/in, cohesive failure). The peel strength of 7-FOX polyurethane onEPDM rubber was 9.5 lbs and the failure was adhesive. Ideally, high peelstrength characterized by cohesive failure is desired (i.e., thematerial will tear before delaminating from the substrate).

The coefficient of dynamic friction is approximately 0.33 for 7-FOX/THFpolyurethanes and 0.31 for 7-FOX polyurethanes. By comparison, thecoefficient of dynamic friction for a typical non-fluorinatedpolyurethane coating containing silicon oil is approximately 0.95.

The above results indicate that the copolymerization of FOX monomerswith THF not only reduces the cost of manufacturing fluorinatedprepolymers, but also provides material with superior properties.Moreover, FOX/THF polyurethanes exhibit better adhesion and superiormechanical properties than FOX polyurethanes, while retaining the keyproperties of FOX polyurethanes such as low glass transitiontemperature, high adhesion, processibility, high hydrophobicity, lowcoefficient of friction, and low surface energy.

Due to their unique combination of properties, polyurethanes preparedfrom FOX/THF co-prepolymers are useful as: fouling release coatings;abrasion resistant, low friction coatings for glass run window channels,belts and windshield wipers; bushing, gaskets, and engine mounts;encapsulants for electronic devices; binders for propellants and flares;artificial joints; dental materials; and coatings for automotive, marineand industrial applications. The preferred applications are foulingrelease coatings, coatings for window channels, and binders forpropellants and flares.

DETAILED DESCRIPTION OF THE BEST MODE

The following detailed description illustrates the invention by way ofexample, not by way of limitation of the principles of the invention.This description will clearly enable one skilled in the art to make anduse the invention, and describes several embodiments, adaptations,variations, alternatives and uses of the invention, including what wepresently believe is the best mode of carrying out the invention.

A. Pre-monomer EXPERIMENTAL SECTION

The following examples detail the two step synthesis process of themono-substituted premonomer. The synthesis of the intermediatedibromoacetate is detailed in Example 1. Example 2 and 3 detail thesynthesis of the 3-bromomethyl-3-methyloxetane premonomer and thearylsulfonate of 3-hydroxymethyl-3-methyloxetane premonomerrespectively. ¹ H/¹³ C NMR analysis was performed on a Bruker MSL-300spectrometer at 300 MHz in CDCl₃ solution with proton and carbon shiftsin ppm relative to tetramethylsilane. IR analysis was performed on aNicolet SX-5 spectrometer.

EXAMPLE A1 Preparation of 3'-bromo-2-bromomethyl-2-methylpropyl Acetate

In a 12L flask equipped with an overhead stirrer, reflux condenser, andaddition funnel was placed 1,1,1-tris(hydroxymethyl)ethane (TME, 1.000Kg, 8.32 mol) and glacial acetic acid (3.750 L). The mixture was allowedto stir until partial dissolution of the TME had occurred and then thesodium bromide (2.568 Kg, 24.96 mol) was added with vigorous stirring.The sulfuric acid (1.718 Kg, 16.64 mol) was then slowly added over 6hours. After the addition was complete, the reaction mixture was heatedto 120° C. for 48 hours. At this time GC evidence indicated that thereaction was complete and the mixture was cooled to room temperature andquenched with 7L of ice water. The organic and aqueous phases wereseparated and the organic was washed with water, 0.5N NaOH (untilneutral pH), brine, and then dried over MgSO₄ to yield the product as aclear colorless oil in 92% yield (2.206 Kg): IR (KBr) 2980-2800, 1744,1374, 1242, 1043, 710 cm⁻¹ ; ¹ H NMR δ1.20 (s, 3H), 2.11 (s, 3H), 3.48(s, 4H), 4.09 (s, 2H); ¹³ C NMR δ20.12, 20.58, 38,21, 39.04, 67.08,170.32.

EXAMPLE A2 Preparation of BrMMO Pre-monomer3-Bromomethyl-3-methyloxetane

In a 50 L flask equipped with an overhead stirrer and reflux condenserwas placed 3-bromo-2-bromomethyl-2-methylpropyl acetate (2.206 Kg, 7.66mol), 3M NaOH (7.67 L, 22.98 mol), tetrabutylammonium bromide (123.47 g,0.383 mol), and CCl₄ (7.66 L). The resulting heterogeneous solution wasthen refluxed at 70° C. overnight. At this time GC evidence indicatedthat the reaction was complete. The reaction was then cooled to roomtemperature. The organic and aqueous phases were separated, the organicphase was washed with water and brine, and then dried over MgSO₄.Removal of the solvent gave the product as a clear, light yellow oil(1.224 Kg) in 97% yield. Distillation gave a clear, colorless oil (1.189Kg) in 94% yield, bp 46° C./0.3 mm Hg; IR (KBr) 2980-2800, 1242, 1201,1147, 704 cm⁻¹ ; ¹ H NMR δ1.44 (s, 3H), 3.65 (s, 2H), 4.40 (d, J=5.8 Hz,2H), 4.45 (d, J=5.8 Hz, 2H) ¹³ C NMR 22.38, 40.58, 41.29, 80.54.

EXAMPLE A3 Preparation of Pre-monomer p-Toluenesulfonate of3-Hydroxymethyl-3-methyloxetane

A solution of 3-hydroxymethyl-3-methyloxetane (612 g, 6 mol) in pyridine(800 ml) was cooled to -10° C. and treated, slowly, with a solution ofp-toluenesufonyl chloride (1364 g, 7 mol) in pyridine (700 ml). The rateof addition was maintained so that the contents of the flask were keptbelow -5° C. Upon complete addition, the solution temperature was heldat -5° C. for 30 minutes and then at room temperature for 2 hours. Thecontents of the flask were quenched by pouring it into ice water (10 L),and the precipitated solid was filtered, washed with water and dried inair. The purity of the product as determined by GLC analysis was >98%.By this method, 1352 g of the desired product was obtained, representingan 88% yield.

The yield and purity of the bromomethyl and arylsulfonate premonomerproduct are extremely high and these examples clearly show how easilyand inexpensively the mono-substituted premonomer of this invention issynthesized.

B. Monomer/Prepolymer Examples Experimental

In the following examples, the polymerization was practiced with borontrifluoride etherate catalyst, although the currently preferred catalystis boron trifluoride tetrahydrofuranate. Commercially available borontrifluoride etherate and boron trifluoride tetrahydrofuranate weredistilled under reduced pressure prior to use. Similarly, the initiator,1,4-butanediol, was purchased commercially and distilled from calciumhydride and stored over a 4 Å molecular sieve prior to use.

The polymerization was conducted in jacketed glass reactors equippedwith a mechanical stirrer reflux condenser and a digital thermometer. ¹H, ¹³ C and ¹⁹ F NMR analysis were conducted on a Bruker MSL-300spectrometer in deutrochloroform solution with proton and carbonchemical shifts reported in parts per million (ppm) relative totetramethylsilane and fluorine shifts relative totrichlorofluoromethane. Infrared analysis was conducted on a NicoletSX-5 spectrometer. Gel permeation chromatography (GPC) was conducted ona Waters gel permeation chromatograph equipped with four ultrastyragelcolumns (1 Å, 500 Å, 10³ Å and 10⁴ Å) a differential refractive indexdetector and a Data Module 730. THF was used as the mobile phase. TheGPC was calibrated with a series of well characterized (i.e., M_(n),M_(w) are well known) polystyrene standards (Narrow Standards), and thusthe number average molecular weight (M_(n)) and weight average molecularweight (M_(w)) reported are expressed relative to styrene. Differentialscanning calorimetry (DSC) was performed on a DuPont 990 thermalanalyzer system at a heating Sate of 10° C./min. Elemental analysis wasconducted by Galbraith Laboratories in Knoxville, Tenn. Inherentviscosity of prepolymers was measured in THF at a concentration of 0.5g/dL at 25° C. Equivalent weights were determined by ¹ H NMR employingtrifluoroacetic anhydride (TFAA) end group analysis. Fluoroalcohols werepurchased commercially from either 3M Corporation or DuPont Corporation,and, with the exception of DuPont's Zonyl BA-L alcohols, were used asreceived. Purification of the Zonyl BA-L alcohols is described inExample B6.

In Examples B1 and B2 we clearly establish proof of the reactionmechanism for the production of the fluorinatedalkoxymethylene-3-methyloxetane monomer using the arylsulfonatepre-monomer.

EXAMPLE B1 Preparation of 3-FOX Monomer3-(2,2,2-Trifluoroethoxymethyl)-3-methyloxetane

Synthesis of the 3-FOX oxetane monomer is performed as follows:

A dispersion of 50 weight percent (2.8 grams, 58.3 mmol) sodium hydridein mineral oil, was washed twice with hexanes and suspended in 35milliliters of dimethyl formamide. Then, 5.2 grams (52 mmol) oftrifluoroethanol was added and the mixture was stirred for 45 minutes. Asolution of 10.0 grams (39 mmol) of 3-hydroxymethyl-3-methyloxetanep-toluenesulfonate in 15 milliliters of dimethyl formamide was added andthe mixture was heated at 75°-85° C. for 20 hours, when ¹ H MNR analysisof an aliquot sample showed that the starting sulfonate had beenconsumed.

The mixture was poured into 100 milliliters of ice water and extractedwith 2 volumes of methylene chloride. The combined organic extracts werewashed twice with water, twice with 2 weight percent aqueoushydrochloric acid, brine, dried over magnesium sulfate, and evaporatedto give 6.5 grams of 3-(2,2,2-trifluoroethoxymethyl)-3-methyloxetane asan oil containing less than 1 weight percent dimethyl formamide. Theyield of this product was 90 percent. The oil was distilled at 30° C.and 0.2 millimeters mercury pressure to give 4.3 grams of analyticallypure 3-FOX, corresponding to a 60 percent yield. The analyses of theproduct were as follows: IR (KBr) 2960-2880, 1360-1080, 990, 840 cm⁻¹ ;¹ H NMR δ1.33 (s, 3H), 3.65 (s,2H), 3.86 (q, J=8.8 Hz, 2H), 4.35 (d,J=5.6 Hz, 2H), 4.51 (d, J=5.6 Hz, 2H); ¹³ C NMR δ20.72, 39.74, 68.38 (q,J=40 Hz), 77.63, 79.41, 124 (q, J=272 Hz). The calculated elementalanalysis for C₇ H₁₁ F₃ O₂ is: C=45.65; H=6.02; F=30.95. The experimentalanalysis found: C=45.28; H=5.83; F=30.59.

EXAMPLE B2 Preparation of 7-FOX Monomer3-(2,2,3,3,4,4,4-Heptafluorobutoxymethyl)-3-methyloxetane

A 50 weight percent dispersion of sodium hydride (6.1 grams, 127 mmol)in mineral oil, was washed twice with hexanes and was suspended in 60milliliters of dimethyl formamide. Then 24.0 grams (120 mmol) of2,2,3,3,4,4,4-heptafluorobutan-1-ol was added and the mixture wasstirred for 45 minutes. A solution of 25.0 grams (97.5 mmol) of3-hydroxymethyl-3-methyloxetane p-toluenesulfonate in 15 milliliters ofdimethyl formamide was added and the mixture was heated at 75°-85° C.for 30 hours when ¹ H NMR analysis of an aliquot showed that thestarting sulfonate had been consumed.

The mixture was poured into 100 milliliters of ice/water and extractedwith two volumes of methylene chloride. The combined organic extractswere washed twice with water, twice with 2 weight percent aqueoushydrochloric acid, brine, dried over magnesium sulfate, and evaporatedto give 27.5 grams of3-(2,2,3,3,4,4,4-heptafluorobutoxymethyl)-3-methyloxetane (i.e., 7-FOX)as an oil. The oil was distilled at 33° C. and 0.2 millimeters mercurypressure to give 12.2 grams of analytically pure ether, corresponding toa 44 percent yield. The experimental analyses were: IR (KBr) 2960-2880,1280-1030, 995, 840 cm⁻¹, ¹ H δ NMR 1.31 (s, 3H), 3.67 (s 2H), 3.99 (t,J=13.3 Hz, 2H), 4.34 (d, J=5.7 Hz 2H), 4.50 (d, J=5.7 Hz, 2H); ¹³ C NMRδ20.242, 39.627, 67.778, 77.730, 79.110, 108.72, 114.7, 117.58; ¹⁹ F NMRδ-81.4, -120.6, -128.1. The calculated elemental analysis for C₉ H₁₁ F₇O₂ is C=38.04; H=3.90; F=46.80. The experimental analyses found:C=38.03; H=3.65; and F=46.59.

Examples B3, B4 and B5 provide detail of the reaction mechanism for thesynthesis of the 15-FOX, 13-FOX and a mixture of 13/17/21-FOX using the3-chloromethyl-3-methyloxetane, the 3-bromomethyl-3-methyloxetane andthe 3-iodomethyl-3-methyloxetanes as the premonomers, respectively. Notethat although the perfluoroalkyl moiety on the side-chain increases insize, the substitution of the fluorinated alkoxide for the halogenproceeds and the yields are high. Further, we have clearly shown by wayof Example B5 that a mixture of perfluorinatedalkoxymethylene-31methyloxetanes may be produced by merely introducing amixture of fluorinated alcohols.

We also show that this reaction works for those fluorinated alcohols inwhich the fluoroalkyl is separated from the hydroxy group by 2methylenes as well as by 1 methylene group (i.e., the process is equallyeffective for the DuPont alcohols as it is for the 3M alcohols).

EXAMPLE B3 Preparation of 15-FOX3-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-Pentadecafluorooctyloxymethyl)-3-Methyloxetane

A dispersion of 50 weight percent sodium hydride (4.0 g, 83 mmol) inmineral oil was washed with hexanes and suspended in 200 milliliters ofdimethylformamide. A solution of 30 grams of2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctan, 1-ol (75 mmol) in 50milliliters of dimethylformamide was added over a period of 3 hours, andthe resulting mixture was stirred at room temperature for one hour.Next, a solution of 9.3 grams (77 mmol) of3-chloromethyl-3-methyloxetane in 20 milliliters of dimethylformamidewas added and the resulting mixture was heated at 75° C. for 16 hours.The mixture was cooled to room temperature and slowly poured into 1liter of ice/water and extracted with two volumes of Freon 113. Thecombined organic extracts were washed twice with water, once with 2weight percent aqueous hydrochloric acid and once with brine, dried overmagnesium sulfate, filtered, and evaporated to give 32 grams of crudeproduct. The crude product was distilled under reduced pressure to give26.5 grams (73%) of analytically pure3-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctoxymethy)-3-methyloxetane(i.e., 15-FOX), an oil with a boiling point of 68° to 70° C./1.6mm-Hg.The experimental analyses were: ¹ H NMR (CDCl₃ /Freon 113) δ4.49 and4.37 (AB, J=5.5 Hz, 4H), 4.00 (triplet, J=13.2 Hz, 2H), 3.70 (singlet,2H), and 1.32 (singlet, 3H); ¹³ C NMR δ21.02, 40.33, 68.77 (triplet,J=146.2 Hz), 78.60, and 79.87 (signals from carbon bearing fluorine arenot included due to complex splitting patterns and low peakintensities); ¹⁹ F NMR δ-81.3 (3F), -119.9 (2F), -122.6 (2F), -123.3(2F), -123.5 (2F), -123.9 (2F) and -126.8 (2F). The elemental analysiswas: Calculated for C₁₃ H₁₁ F₁₅ O₂ : C, 32.2; H, 2.3; F, 58.9. Found: C,32.2; H, 2.2; F, 58.3.

EXAMPLE B4 Preparation of 13-FOX3-(3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyloxymethyl)-3-Methyloxetane

In a manner similar to that described above, 12.0 grams of3-bromomethyl-3-methyloxetane (73 mmol) was reacted with 26.5 grams of3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctan-1-ol (72.7 mmol) in 300milliliters of dimethylformamide in the presence of 3.9 grams of a 50weight percent dispersion of sodium hydride (81 mmol) in mineral oil at85° C. for 24 hours to give 21.5 grams (70% yield) of3-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyloxymethyl)-3-methyloxetane,a colorless oil with a boiling point of 66°-68° C./2-2.5 mm-Hg; ¹ H NMR(CDCl₃) δ4.50 and 4.36 (AB, J=5.5 Hz, 4H), 3.78 (t, J=6.6 Hz, 2H), 3.53(s, 2H), 2.42 (triplet of triplets, J=6.6 and 18 Hz, 2H), and 1.31 (s,3H); ¹³ C NMR (CDCl₃) δ79.89, 78.30, 63.31, 39.9, 31.64 (t), and 21.1(signals due to carbons bearing fluorines are not included due to thecomplex splitting patterns and low peak intensities); ¹⁹ F NMR δ-81.4(3F), -113.8 (2F), -118.2 (2F), -112.3 (2F), -124.1 (2F) and -126.7(2F). The elemental analysis was: Calculated for C₁₃ H₁₃ F₁₃ O₂ : C,34.8; H, 2.9; F, 55.1. Found: C, 35.1; H, 3.0; F, 54.7.

Note that the fluorinated alcohols in Examples B4 and B6 were suppliedby DuPont (i.e., R_(f) --CH₂ CH₂ OH). These alcohols are inexpensive andavailable in bulk, however, they are not pure and must be purified priorto use in these reactions. Example B5 details how these fluoroalcoholsmay be purified. On the other hand, the fluoroalcohols of Examples B1,B2 and B3 have a methanol group pendant to the perfluoroalkyl moiety(i.e., R_(f) --CH₂ OH) and are purchased From 3M Corporation as reagentgrade, not requiring further purification.

EXAMPLE B5 Purification of Commercial Fluoroalcohols

Zonyl BA-L is a narrow distribution, oligomeric mixture offluoroalcohols that is available from Dupont Chemicals in pilot plantquantities. Zonyl BA-L is a yellow liquid which by GLC is a mixture ofthe following oligomers:3-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctan-1-ol (C8, 60%);3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecan-1-ol (C10,26%);3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-heneicosafluorododecanol(C12, 6%); and various unidentified high boiling compounds (8%). ZonylBA-L was washed with equal volumes of 10 weight percent aqueous sodiumthiosulfate, 10 weight percent aqueous sodium bicarbonate (to removeHF), water and brine, dried, filtered, and distilled under reducedpressure (3mm-Hg) at 50°-100° C. to give a mixture of 69% C8, 26% C10and 5% C12 in 83% yield.

EXAMPLE B6 Preparation of a Mixture: 13/17/21-FOX3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyloxymethyl-,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-Heptadecafluorodecyloxymethyl-,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-Heneicosafluorododecylocymethyl-3-Methyloxetane

In a manner similar to that described above, a mixture of 69% C8, 26%C10 and 5% C12 fluoroalcohols (distilled Zonyl BA-L from Example B5,51.6 grams, 129 mmol) was reacted with 27 grams of3-iodomethyl-3-methyloxetane (127 mmol) in 500 milliliters ofdimethylformamide at 85° C. for 18 hours to give 60 grams of crudeproduct. The crude product was fractionally distilled through a 6"Vigerux column to yield the following fractions: Fraction #1 (4.8 grams)was collected between 25° C. and 45° C. at 3.5-2.9 mm-Hg, and was amixture of unreacted fluoroalcohols. Fraction #2 (2.8 grams) wascollected at 45°-71° C./0.7-3.0 mm-Hg, and was a mixture of unreactedfluoroalcohols and fluorinated oxetane monomers. The final fraction (49grams, 80%), boiling at 70°-85° C./0.7-0.9 mm-Hg, was a mixture of 73%3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyloxymethyl-3-methyloxetane(13-FOX), 24%3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyloxymethyl-3-methyloxetane(17-FOX), and 3%3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-heneicosafluorododecyloxymethyl-3-methyloxetane(21-FOX), a colorless oil with a boiling point of 70°-85° C./0.7-0.9mm-Hg; ¹ H NMR (CDCl₃) δ4.50 and 4.35 (AB, J=5.9 Hz, 4H), 3.78 (t, J=6.6Hz, 2H), 3.53 (s, 2H), 2.42 (tt, J=6.6 and 17.6 Hz, 2H), and 1.31 (s,3H); ¹³ C NMR δ21.3, 31.86 (t, J=130.1 Hz), 40.2, 63.6, 76.8, and 80.2(signals for carbons bearing fluorine are not included due to complexsplitting patterns and overlap of signals; ¹⁹ F NMR δ-81.5, -113.8,-122.3, -123.3, -124.1, -124.5, -125.8, and 126.7.

Phase Transfer Catalyst Process

Examples B7 and B8 provide details as to the preferred process forsynthesizing the FOX monomers of this invention using a phase transfercatalyst (PTC).

EXAMPLE B7 Preparation of 7-FOX Using PTC Process3-(2,2,3,3,4,4,4-Heptafluorobutoxymethyl)-3-Methyloxetane

A 2 L, 3 necked round bottom flask fitted with a reflux condenser, amechanical stirrer, a digital thermometer and an addition funnel wascharged with 3-bromomethyl-3-methyloxetane (351.5 g, 2.13 mol),heptafluorobutan-1-ol (426.7 g, 2.13 mol), tetrabutylammonium bromide(34.4 g) and water (85 ml). The mixture was stirred and heated to 75° C.Next, a solution of potassium hydroxide (158 g, 87% pure, 2.45 mol) inwater (200 ml) was added and the mixture was stirred vigorously at80°-85° C. for 4 hours. The progress of the reaction was monitored byGLC and when GLC analysis revealed that the starting materials wereconsumed, the heat was removed and the mixture was cooled to roomtemperature. The reaction mixture was diluted with water and the organiclayer was separated and washed with water, dried and filtered to give566 g (94%) of crude product. The crude product was transferred to adistillation flask fitted with a 6 inch column and distilled as follows:

Fraction #1, boiling between 20° C.-23° C./10mm-Hg, was found to be amixture of heptafluorobutanol and other low boiling impurities, wasdiscarded;

Fraction #2, boiling between 23° C. and 75° C./1 mm-Hg, was found to bea mixture of heptafluorobutanol and 7-FOX, was also discarded; and

Fraction #3, boiling at 75° C./1 mm-Hg was >99% pure 7-FOX representingan overall yield of 80.2%

NMR and GLC data revealed that 7-FOX produced by this method wasidentical to 7-FOX prepared using the sodium hydride/DMF process.

EXAMPLE B8 Preparation of 15-FOX Using PTC Process3-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-Pentadecafluorooctyloxymethyl-3-Methyloxetane

In a manner similar to the that of Example B14, a mixture of3-bromomethyl-3-methyloxetane (468 g, 2.84 mol),2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctan-1-ol (1032 g, 2.58mol), tetrabutylammonium bromide (41.5 g), potassium hydroxide (208 g,3.23 mol), and water (1680 ml) was heated under reflux for 3 hours. GLCanalysis revealed complete consumption of starting materials. Thereaction mixture was diluted with water, worked-Up in the usual manner,and distilled under reduced pressure to give 1,085 g of 15-FOX,representing an overall yield of 87%; bp 82° C./0.1mm-Hg. The distilledmaterial was >99% pure as indicated by GLC and was used in subsequentpolymerization reactions.

The first of three Comparative Examples below show that we are able toeasily synthesize, using the process of our invention, in high yield,the bis-equivalent to our 3-FOX monomer.

In the second Comparative Example we show that we can easilyhomopolymerize, using the process of our invention, the bis 3-FOX toproduce the bis 3-FOX prepolymer. As expected and consistent with thetechnology of Falk et al., the bis-prepolymer of this ComparativeExample was a white waxy crystalline solid, unlike the low viscosityoils of the prepolymers of this invention. This is attributable to theordered structure of the fluoroalkoxy side-chains resulting in efficientpacking of the prepolymers into a crystalline structure.

In the third Comparative Example we show that a bis-monomer having muchlonger fluoroalkoxy side-chains may still be homopolymerized by theprocess of this invention. In other words, the homopolymerization of the5is-monomer is not limited by the size of the fluoroalkoxy groups. Thisis unexpected in view of the difficulties described in the background inachieving homopolymerization of the bis-substituted oxetanes. However,we observe that as the fluorinated side-chains of the bis-monomer becomelarger, homopolymerization results in a much higher fraction of theundesirable, non-functional cyclic tetramer. In our third ComparativeExample the initial fraction of the cyclic tetramer byproduct is 32%.Even after further purification, the cyclic tetramer was still presentat 9%. It is hypothesized that the presence of the cyclic tetramerimpurity resulted in the prepolymer being a liquid rather than theexpected solid, as it is well known that impurities will preventcrystallization. Increasing the size, of the fluorinated side-chainsresults in increasing yields of the cyclic tetramer impurity and loweryields of the prepolymer. This suggest that the homopolymerization ofthe bis-monomer, although possible by the process of this invention, maynot be commercially desirable for those bis-monomers having largerside-chains. In comparison, the FOX prepolymers of this invention do notexhibit decreasing yields/quality with increasing side-chain length.Consequently, the FOX prepolymers of this invention make possible theeconomic production of fluorinated polyurethanes having outstandingsurface properties (see Exhibit 1).

COMPARATIVE EXAMPLE B9-a Preparation of Bis-3-FOX3,3-Bis-(2,2,2-trifluoroethoxymethyl)oxetane

A 50 weight percent dispersion of sodium hydride in 18.4 grams (0.383mol) of mineral oil, was washed twice with hexanes and was suspended in200 milliliters of dimethyl formamide. Then, 38.3 grams (0.383 mol)trifluoroethanol was added dropwise over 45 minutes while hydrogen gasevolved. The mixture was stirred for 30 minutes and a solution of 30.0grams (0.073 mol) of 3,3-bis(hydroxymethyl)oxetane di-p-toluenesulfonatein 50 milliliters of dimethyl formamide was added. The mixture washeated to 75° C. for 64 hours when ¹ H NMR analysis of an aliquot showedthat the starting sulfonate had been consumed.

The mixture was poured into water and extracted with two volumes ofmethylene chloride. The combined organic extracts were washed withbrine, 2 weight percent aqueous hydrochloric acid, water, dried overmagnesium sulfate, and evaporated to give 17.5 grams of3,3-bis(2,2,2-trifluoroethoxymethyl)oxetane as an oil containing lessthan 1 weight percent dimethyl formamide. The oil was purified bybulb-to-bulb distillation at 42°-48° C. and 10.1 millimeters mercurypressure to give 15.6 grams of analytically pure bis-3-FOX,corresponding to a 79 percent yield. The analyses of the product were asfollows: ¹ H NMR δ3.87 (q, J=8.8 Hz, 4H), 4.46 (s, 4H); ¹³ C NMR δ43.69,68.62 (q, J=35 Hz), 73.15, 75.59, 123.87 (q, J=275 Hz); ¹⁹ F NMR δ-74.6(s). The calculated elemental analysis for C₉ H₁₂ F₆ O₃ is: C=38.31;H=4.29; and F=40.40. The experimental analyses found: C=38.30; H=4.30;and F=40.19.

COMPARATIVE EXAMPLE B9-b Preparation of the Bis-3-FOX Prepolymer Poly3,3-bis(2,2,2-trifluoroethoxymethyl)oxetane

A solution of 33.9 milligrams (0.378mmol) of butane-1,4 diol and 106.3milligrams (0.75mmol) of boron trifluoride etherate in 3.8 grams ofmethylene chloride was stirred at ambient temperature for 15 minutesunder nitrogen in a dry polymerization flask. The solution was cooled to1.5° C. and a solution of 1.88 grams (6.67 mmol) of3,3-bis(2,2,2-trifluoroethoxymethyl)oxetane in 2.3 grams of methylenechloride was added. The resultant solution was stirred for 16 hours at1°-2° C. at which time ¹ H NMR analysis of an aliquot indicated that thestarting oxetane had been consumed.

The solution was warmed to ambient temperature and quenched with water.The organic layer was washed with brine, 2 percent aqueous hydrochloricacid, and evaporated to give 1.62 grams of poly3,3-bis(2,2,2-trifluoroethoxymethyl)oxetane, corresponding to 85% yield.The prepolymer was a white, wary solid. The polymer analyses were: DSCmp 80.96° C. (26.35 Joules/gram); GPC: M_(n) =5321, M_(w) =7804,polydispersity=1.47; inherent viscosity 0.080 dL/g; ¹ H NMR δ1.60 (broadsinglet), 3.36 (s, 4H), 3.58 (s, 4H), 3.79 (q, 4H); ¹³ C NMR 45.49,68.25 (q, J=33 Hz), 69.20, 70.97, 123.81 (q, J=280 Hz).

COMPARATIVE EXAMPLE B9-c Homopolymerization of Bis-Monomer3,3-Bis(2,2,3,3,4,4,4-Heptafluorobutoxymethyl) Oxetane

In a manner similar to that described in Example B7-b, a solution of 252grams of 3,3-bis(2,2,3,3,4,4,4-heptafluorobutoxymethyl) oxetane (523mmol) in 75 milliliters of Freon 113 was added to a mixture of 1.05grams of boron trifluoride tetrahydrofuranate (7.5 mmol) and 0.265 gramof 1,4-butanediol (2.93 mmol) in 178 milliliters of methylene chlorideat 10° C. The mixture was stirred at room temperature for 48 hours atwhich time NMR analysis of an aliquot indicated 96 percent conversion.The reaction was quenched with water and the polymer was precipitatedinto methanol to give, after drying at 80° C./2 mm-Hg for 16 hours, 211grams of poly 3,3-bis (2,2,3,3,4,4,4-heptafluorobutoxymethyl) oxetane, acolorless oil in 84 percent yield. GPC analysis of this oil revealed itwas a mixture of 68% linear and 32% cyclic materials. The cyclic productwas isolated and identified as the cyclic tetramer, a white wary solidwith a melting point of 80° C.; ¹ H NMR δ 3.87 (t, J=13.5 Hz, 4H), 3.54(s, 4H), and 3.32 (S, 4H) (No end groups were observed on addition oftrifluoroacetic anhydride); ¹³ C NMR δ71.2, 68.6, 68.4 (t), and 46.2(signals due to carbons bearing fluorine are not included).

The above oil was further purified by first dissolving the material inmethylene chloride/Freon 113 (75:25 mixture), precipitating the polymerinto a 10 fold excess of methanol, stirring the precipitated oil withtetrahydrofuran at room temperature for 2 days, and finally separatingand drying the insoluble fraction at 85° C. at 2 mm-Hg for 16 hours.This yielded 128 grams of a clear, viscous oil, corresponding to 51%overall yield. The oil by GPC analysis was determined to be a mixture of91% linear polymer and 9% cyclic tetramer. The polymer analyses were:GPC: M_(n) =5,526, M_(w) =7,336, polydispersivity=1.32; ¹ H NMR (CDCl₃/Freon 113/TFAA) δ3.39 (s, 4H), 3.59 (s, 4H), 3.87 (t, J=13.5 Hz, 4H)and 4.40 (s, --C H₂ OCOCF₃); Equivalent Weight based on ¹ H NMR=2,600;¹³ C NMR (CDCl₃ Freon 113) δ46.4, 68.5 (t), 70.1 and 72.1 (signals fromcarbons bearing fluorines are not included).

Examples B10 through B15 provide details on the polymerization of theFOX monomers to provide the FOX prepolymers of this invention.

Examples B10, B11 and B12 detail the homopolymerization of the 3-FOX,7-FOX and 13-FOX respectively to provide random, asymmetricalprepolymers. Note that the yield of the 7-FOX prepolymer of Example B11produced from the 7-FOX mono-substituted monomer resulted in a muchhigher yield of the prepolymer than that obtained from the bis-7-FOXhompolymerization of Comparative Example B9-c (83% versus 51%).

Example B12 uses the preferred BF₃.THF catalyst.

EXAMPLE B10 Homopolymerization of 3-FOX3-(2,2,2-Trifluoroethoxymethyl)-3-methyloxetane

A solution of 34.3 milligrams (0.38 mmol) of butane-1,4-diol and 109.7milligrams (0.77 mmol) of boron trifluoride etherate in 4 grams ofmethylene chloride was stirred at ambient temperature for 15 minutesunder nitrogen in a dry polymerization flask. The solution was cooled to1.5° C. and a solution of 1.20 grams (6.52 mmol) of3-(2,2,2-trifluoroethoxymethyl)-3-methyloxetane in 1.3 grams ofmethylene chloride was added. The resultant solution was stirred for 5hours at 1°-2° C. at which time ¹ H NMR analysis of an aliquot indicatedthat the starting oxetane had been consumed. The solution was warmed toambient temperature and quenched with water. The organic layer waswashed with brine, 2 weight percent aqueous hydrochloric acid, andevaporated to give 1.053 grams ofpoly-3-(2,2,2-trifluoroethoxymethyl)-3-methyloxetane as an oil,corresponding to a 88 percent yield. The polymer analyses were: DSC Tg-45° C., decomposition temperature was greater than 200° C.; GPC M_(n)=7376, M_(w) =7951, polydispersity 1.08, inherent viscosity 0.080 dL;Equivalent Weight by ¹ H NMR=6300; ¹ H NMR δ0.95 (s, 3H), 3.26 (m, 4H),3.52 (s, 2H) 3.84 (q. 2H); ¹³ C NMR δ17.57, 42.09, 69.30 (q, J=33 Hz),74.42, 75.90, 125.18 (q, J=280 Hz).

EXAMPLE B11 Homopolymerization of 7-FOXPoly-3-(2,2,3,3,4,4,4-heptafluorobutoxymethyl)-3-methyloxetane

A solution of 34.7 milligrams (0.38 mmol) of butane-1,4-diol and 109.7milligrams (0.77mmol) of boron trifluoride etherate in 3.4 grams ofmethylene chloride was stirred at ambient temperature for 15 minutesunder nitrogen in a dry polymerization flask. The solution was cooled to1.5° C. and a solution of 2.00 grams (7.08 mmol) of3-(2,2,3,3,4,4,4-heptafluorobutoxymethyl)-3-methyloxetane (i.e., 7-FOX)in 3.3 grams of methylene chloride was added. The resultant solution wasstirred for 4 hours at 1.2° C.; at which time ¹ H NMR analysis of analiquot indicated that the starting oxetane had been consumed.

The solution was warmed to ambient temperature and quenched with water.The organic layer was washed with brine, 2 percent aqueous hydrochloricacid, and evaporated to give 1.65 grams ofpoly-3-(2,2,3,3,4,4,4-heptafluorobutoxymethyl)-3-methyloxetane,corresponding to a 83% yield. The prepolymer was an oil and had thefollowing analyses: GPC M_(n) =4066, M_(w) =5439, polydispersity=1.34,inherent viscosity 0.054 dL/g.

This oil was further extracted with methanol and dried to give 1.46grams of poly-7-FOX, corresponding to 72% yield, and has the followinganalyses: DSC: Tg=-45° C.; GPC: M_(n) =4417, M_(w) =5658,polydispersity=1.28; inherent viscosity=0.056 dL/g; Equivalent weight by¹ H NMR=6359, ¹ H NMR δ0.93 (s, 3H), 3.24 (m, 4H), 3.48 (s. 2H), 3.92(q, J=13.6 Hz, 2H); ¹³ C MMR 16.14, 40.57, 67.37 (t), 72.89, 74.76(signals from carbon-bearing fluorie are not included).

EXAMPLE B12 Homopolymerization of 13-FOX3-(3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyloxymethyl)-3-Methyloxetane

In a manner similar to that described in Example B9, a solution of 10grams of3-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyloxymethyl)-3-methyloxetane(22.3 mmol) in three milliliters of Freon 113 was added dropwise to amixture of 109 milligrams of boron trifluoride tetrahydrofuranate (0.78mmol) and 35 milligrams of 1,4-butanediol (0.39 mmol) in methylenechloride at 10° C. The mixture was stirred at room temperature for 24hours, quenched with water, and precipitated in methanol to give, afterdrying at 80° C./2 mm-Hg for 16 hours, 8.3 gram of poly3-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyloxymethyl)-3-methyloxetane,a clear colorless oil. The polymer analyses were: Inherentviscosity=0.067 dL/g; GPC: M_(n) =5,340, M_(w) =6,620, PolyDispersity=1.24; DSC, Tg=-38° C.; ¹ H NMR (CDCl₃ /Freon113/trifluoroacetic anhydride (TFAA)) δ3.67 (t, 5.9 Hz, 2H), 3.31 (s,2H), 3.21 (m, 4H), 2.35 (m, 2H), and 0.93 (s, 3H); ¹ H NMR (CDCl₃ /Freon113) 0.95 (s, 3H), 2.37 (br t, J=18.3 Hz, 2H), 3.25 (m, 4H), 3.35 (s,2H), 3.71 (t, 6.0 Hz, 2H), and 4.30 (s, --C H₂ OCOCF₃); EquivalentWeight based on ¹ H NMR was 4,756, ¹³ C NMR (CDCl₃ Freon 113) δ17.35,31.75, 41.5, 63.4, 74.1 and 74.3 (signals from carbon bearing fluorineare not included).

Examples B13-B15 provide details as to the copolymerization of variousFOX monomers to provide FOX co-prepolymers. The polymerization in allthree Examples is catalyzed with BF₃ -THF. Noteworthy is the high yieldsin the 80%-85% in all three Examples.

EXAMPLE B13 Copolymerization of 3-FOX and 7-FOX3-(2,2,2,-Trifluoroethoxymethyl)-3-Methyloxetane with3-(2,2,3,3,4,4,4-Heptafluorobutoxymethyl)-3-Methyloxetane

In a manner similar to that described in Example B9, a solution of 35grams of 3-(2,2,2,-trifluoroethoxymethyl)-3-methyloxetane (190 mmol) and183 grams of 3-(2,2,3,3,4,4,4-heptafluorobutoxymethyl)-3-methyloxetane(644 mmol) in 50 milliliters of 1,1,2-trichlorotrifluoroethane was addedto a mixture of 0.390 gram of 1,4-butanediol (4.33 mmol), 1.55 grams ofboron trifluoride tetrahydrofuranate (11.1 mmol), and 100 milliliters ofmethylene chloride at 18° C. The mixture was stirred at 18° C. for 3hours, quenched with water, and precipitated into methanol to give,after drying at 85° C.B 2 mm-Hg for 16 hours, 186 grams of a clear,colorless oil, corresponding to 85%.yield. NMR analysis revealed thatthis material was a 22:78 random copolymer of the above two monomers.

The polymer analyses were: DSC, T_(g) =-42° C.; GPC: M_(n) =15,660,M_(w) =30,640; Polydispersity=1.96; Equivalent Weight by ¹ H NMR was9,200; Inherent viscosity=0.071; ¹ H NMR (CDCl₃ /Freon 113) δ0.91 (s, CH₃), 3.22 (m, backbone --C H₂), 3.44 (s, --C H₂ O), 3.79 (q, J=8.8 Hz,--C H₂ CF₃) and 3.86 (t, J=13.5 Hz, --C H₂ C₃ F₇); ¹ H NMR CDCl₃ Freon113L Trifluoroacetic anhydride) δ0.95 (s, --C H₃), 3.23 (m, backbone-CH₂ 'S), 3.46 (s, --C H₂ C₃ O), 3.77 (q, J=8.6 Hz, --C H₂ CF₃), 3.87 (t,J=13.5 Hz, --C H₂ C₃ F₇), and 4.31 (s, --C H₂ OCOCF₃); ¹³ C NMR (CDCl₃Freon 113) δ17.3, 41.6, 41.8, 68.6 (t), 69.3 (q), 74.2, 75.6, and 75.9(signals from carbons bearing fluorine are not included).

In a similar manner, random copolymers of above monomers in 50:50 and75:25 ratios were also prepared. The copolymers were clear, colorlessoils that were soluble in tetrahydrofuran., methylene chloride and1,1,2-trichlorotrifluoroethane (Freon 113).

EXAMPLE B14 Copolymerization of 3-FOX and 15-FOX3-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-Pentadecafluorooctyloxymethyl)-3-Methyloxetanewith 3-(2,2,2-Trifluoroethoxymethyl)-3-Methyloxetane

A one-liter, three-necked, round-bottomed flask was fitted with amechanical stirrer, nitrogen inletutlet tubes, a reflux condenser, athermometer, and a constant addition funnel. The apparatus was driedwith a heat gun, cooled under nitrogen to room temperature, and chargedwith a mixture of 0.914 grams of trimethylolpropane (TMP, 6.52 mmol),3.1 grams of boron trifluoride tetrahydrofuranate (22 mmol), 160milliliters of 1,1,2-trichlorotrifluoroethane and 30 milliliters ofanhydrous methylene chloride. The mixture was stirred at roomtemperature for 30 minutes, cooled to 10° C., and then treated,dropwise, with a solution of 106 grams of3-(2,2,2-trifluoroethoxymethyl)-3-methyloxetane (576 mmol) and 94 gramsof3-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyloxymethy)-3-methyloxetane(195.2 mmol) in 40 milliliters of 1,1,2-trichlorotrifluoroethane. A mildexotherm was observed in addition of the monomer. The reactiontemperature was maintained at 18° C. for 2 hours and then at 25° C. for4 hours at which time NMR analysis of an aliquot indicated that 98percent of the oxetane monomers were consumed. The reaction mixture wasdiluted with 50 milliliters of methylene chloride and 50 milliliters of1,1,2,-trichlorotrifluoroethane, and quenched with 50 milliliters ofwater. The organic layer was separated, washed with two equal volumes ofwater, and added dropwise to a 10 fold excess of methanol at roomtemperature. The precipitated oil was separated and redissolved in a50:50 mixture of methylene chloride and 1,1,2-trichlorotrifluoroethaneand transferred to a 500-milliliter, round-bottomed flask. The solventwas evaporated under reduced pressure and the resulting oil was dried at85° C./2mm-Hg for 16 hours to give 170 grams of a clear, colorless,viscous oil, corresponding to 85 percent yield. The NMR analyses of thismaterial indicated it was a random copolymer of the above two monomersin a 74:26 ratio. The polymer analyses were: DSC, T_(g) =-40° C.; GPC:M_(n) =6,178, M₂ =7,286, Polydispersity=1.18; Equivalent Weight by ¹ HNMR was 3,520; Inherent viscosity was 0.065; ¹ H NMR (CDCl₃) δ0.94 (s,--C H₃), 3.23 (m, backbone--C H₂ 'S), 3.47 (s, --C H₂ O), 3.75 (q, J=8.6Hz, --C H₂ CF₃) and 3.85 (t, J=13.5 Hz, --C HC₃ F₇); ¹ H NMR (CDCl₃Trifluoroacetic anhydride) δ1.00 (s, --C H₃), 3.37 (m, backbone --C H₂'S), 3.49 (s, --C H₂ O), 3.78 (q, J=8.6 Hz, --C H₂ CF₃), 3.96 (t, J=13.5Hz, --C HC₃ F₇), and. 4.30 (s, C H₂ OCOCF₃); ¹³ C NMR (CDCl₃) δ17.1,41.2, 41.3, 68.5 (t), 68.9 (q), 73.7, 75.3 and 75.5.

In a manner similar to that described above, random copolymers of abovemonomers in 50:50, 33:67, 25:75 and 10:90 ratios were also prepared.These copolymers were clear, colorless oils that wee soluble in asolvent mixture of methylene chloride and1,1,2,-trichlorotrifluoroethane.

EXAMPLE B15

Copolymerization of a mixture of 13-FOX, 17-FOX and 21-FOX

3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyloxymethyl-,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-Heptadecafluorodecyloxymethyl-, and3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-Heneicosafluorododecyloxymethyl-3-Methyloxetanes

In a manner similar to that described in Example B12, a solution of 30grams of 13-FOX (73%), 17-FOX (24%), and 21-FOX (3%) monomers (62 mmol)in 10 milliliters of Freon 113 was added dropwise to a mixture of 300milligrams of boron trifluoride tetrahydrofuranate (2.14 mmol) and 95milligrams of 1,4-butanediol (1.05 mmol) in 30 milliliters of methylenechloride at 10° C. The mixture was stirred at room temperature for 24hours, quenched with water, and precipitated in methanol to give, afterdrying at 80° C.B 2 mm-Hg for 16 hours, 24 grams of the title copolymer,corresponding to 80 percent yield. The copolymer was a colorless,viscous oil. The analysis of the co-prepolymer was: Inherentviscosity=0.075 dL/g; GPC: M_(n) =6,639, M_(w) =9,368,Polydispersity=1.41; ¹ H NMR (CDCl₃ Freon 113/TFAA) δ0.95 (s, 3H), 2.37(br t, J=18.3 Hz, 2H), 3.25 (m, 4H), 3.35 (s, 2H), 3.71 (t, 6.0 Hz, 2H),and 4.30 (AB, --C H₂ OCOCF₃); Equivalent Weight based on ¹ H NMR was2,510; ¹³ C NMR (CDCl₃ Freon 113) δ17.35, 31.75 (5), 41.1, 41.5, 63.4,74.1 and 74.3.

C. ELASTOMERS

The FOX prepolymers of this invention can be cured with diisocyanates orpolyisocyanates for the production of polyurethane elastomers. Detaileddescriptions of the preferred method of making these elastomers areprovided below.

EXPERIMENTAL

Mechanical properties (Stress-Strain analysis ) were measured with aModel 1122 Instron tester. Static Contact angles of water with thepolymer surface were measured with a Goniometer using doubly distilledwater. Differential scanning calorimetry (DSC) and ThermogravimetricAnalysis (TGA) were performed on a DuPont 990 thermal analyzer system.DSC measurements were made at a heating rate of 10° C.in in air, whereasTGA measurements were made at a heating rate of 20° C./min in air at aflow rate of 20 mL/min. Peel strength was measured with an Instron.Chemical resistance was measuredly immersing the samples in selectedsolvents, removing the samples from the solvent after 24 h, andmeasuring the change in weight and dimensions. Surface energy wasmeasured by the method of Wu et al. Isocyanates such as isophoronediisocyanate (IPDI), saturated methylenediphenyl diisocyanate (Des-W),N-100 and N3200 were obtained from Mobay Chemical Co. Isopheronediisocyanate (IPDI), was distilled prior to polymerization.4,4'-Methylene dianiline (MDA) and solvents were purchased from AldrichChemical Co., where as Jeffamine was obtained from Texaco Corporation.Isonal 93 was obtained from Dow Chemical Corporation.

EXAMPLE C1 Preparation of Poly 7-FOX/Des-W/Isonol Polyurethane Elastomer

This example illustrates the preparation of a polyurethane elastomerfrom the Homo-prepolymer of3-(2,2,3,3,4,4,4-heptafluorobutoxymethyl)-3-methyloxetane (Poly 7-FOX)with the Des-W diisocyanate and the Isonol 93 cross-linker.

Note that the surface energy of the resulting 7-FOX polyurethane is 13.2ergs/cm² which is a significant improvement over the surface energy ofTeflon at 18.5 ergs/cm².

Procedure A (No solvent; casting a bulk article)

A 50 mL, 3-necked flask was dried with a heat gun under nitrogen andcharged with Poly 7-FOX (10,005 g, 2.22 meq), Isonol 93 (107 mg, 1.21meq), Des-W (469 mg, 98.5% pure, 3.50 meq), and dibutyltin dilaurate (3mg). The contents were mixed and casted into a Teflon mold. The mixturewas then degassed, placed in an oven, and cured at 65° C. for 16 h. Thepolymer sample was removed from the mold and characterized as follows:

    ______________________________________                                        Nature:            Tack-free Elastomer                                        Color:             Opaque                                                     Static Contact Angle (H.sub.2 O)                                                                 117°                                                Surface Energy     13.2 ergs /cm.sup.2                                        Mechanical Properties                                                         Tensile Modulus    41 psi                                                     Elongation at Break                                                                              1308%                                                      Tensile Strength   622 psi                                                    Hardness           7 Shore A                                                  Glass Transition Temperature, DSC                                                                -45° C.                                             Thermal Stability, TGA                                                                           0% Wt. Loss to 260° C.                              Onset of major degradation                                                                       275° C.                                             Peel Strength, EPDM Rubber                                                                       9.5 lb/in, Adhesive Failure                                Water Absorption                                                              9 days/25° C.                                                                             0.16% by Weight Gain                                       16 h/100° C.                                                                              0.28% by Weight Gain                                       Chemical Resistance                                                           Stable             Methanol, hexane, toluene,                                                    20% sodium hydroxide, non-                                                    leaded gasoline, & DMF                                     Swell              THF, MTBE and Freon 113                                    ______________________________________                                    

EXAMPLE C2 Preparation of Poly 3/7-FOX/IPDI/MDA Polyurethane Elastomer

This example illustrates the preparation of polyurethane elastomer froma 25:75 Co-prepolymer of 3-(2,2,2-trifluoroethoxymethyl)-3-methyloxetaneand 3-(2,2,3,3,4,4,4-heptafluorobutoxymethyl)-3-methyloxetane (Poly3/7-FOX, 25:75).

Note that this Example describes polymerization in a solvent, thereforethe solution can be used to prepare thin polyurethane elastomercoatings. Application of the coating may be by any conventional meansincluding dip-coating, spray coating, etc.

Procedure B (Polymerization in solvent for a bulk or coated article):

A 50 mL, 3-necked round bottom flask fitted with a condenser, amechanical stirrer, thermometer, and a nitrogen inlet/outlet was driedunder nitrogen and charged with the title co-prepolymer (2.93 g, 0.651meq), IPDI (0.298 g, 2.68 meq), dibutyltin dilaurate (16 mg), andanhydrous tetrahydrofuran (6 mL). The mixture was heated under refluxfor 2.5 h, cooled to room temperature and treated with a solution ofmethylene dianiline (0.120 g, 98.5% pure, 2.38 meq) in tetrahydrofuran(1.5 mL). The resulting yellow solution was stirred at room temperaturefor 16 h, casted into a teflon mold*, and the solvent was slowlyevaporated at room temperature to give a yellow tacky material. Thismaterial was cured at 65° C. for 24 h to give a tough, tack-free,elastomer. This material exhibited a contact angle with water of 112°.The mechanical properties of this elastomer were: tensile modulus, 48psi; elongation at break, 941%; and tensile strength, 214 psi. Thepolymer sample was insoluble in methanol, toluene, ethanol and hexane,but swelled in Freon 113 and THF.

EXAMPLE C3 Preparation of Poly 3/7-FOX/IPDI/TMP Polyurethane Elastomer

This example illustrates the preparation of polyurethane elastomer froma 25:75 Co-prepolymer of 3-(2,2,2-trifluoroethoxymethyl)-3-methyloxetaneand 3-(2,2,3,3,4,4,4-heptafluorobutoxymethyl)-3-methyloxetane (Poly 3/7FOX, 25:75) by Procedure A as in Example C1 and using TMP as across-linking agent.

A 25 mL, 3-necked flask was dried with a heat gun under nitrogen andcharged with the title co-prepolymer (5,007 g, 1.35 meq), TMP (208 mg,4.66 meq), IPDI (682 mg, 6.12 meq), and dibutyltin dilaurate (6 mg, 0.1%wt.). The contents were mixed and casted into a Teflon mold. The mixturewas then degassed, placed in an oven, and cured at 65° C. for 16 h. Thecured material was removed from the mold and characterized as follows:

    ______________________________________                                        Nature:            Tack-free Elastomer                                        Color:             Opaque                                                     Static Contact Angle (H.sub.2 O)                                                                 114°                                                Surface Energy     15.4 ergs/cm.sup.2                                         Mechanical Properties                                                         Tensile Modulus    34 psi                                                     Elongation at Break                                                                              1256%                                                      Tensile Strength   427 psi                                                    Hardness           5 Shore A                                                  Glass Transition Temperature, DSC                                                                -42° C.                                             Water Absorption                                                              9 days/25° C.                                                                             0.22% by Weight Gain                                       16 h/100° C.                                                                              0.25% by Weight Gain                                       Chemical Resistance                                                           Stable             Methanol, Hexane, Toluene,                                                    20% Sodium hydroxide, and                                                     DMF                                                        Swell              THF and Freon 113                                          ______________________________________                                    

EXAMPLE C4 Preparation of Poly 3-FOX/Des-W/Isonol Polyurethane Elastomer

This example illustrates the preparation of polyurethane elastomer fromthe homo-prepolymer of 3-(2,2,2-trifluoroethoxymethyl)-3-methyloxetane(Poly 3-FOX) by Procedure A. This Example is the same as in Example C1except that Example C1 uses the 7-FOX.

Note that although the resulting 3-FOX polyurethane elastomer containsonly 29% fluorine as compared to Teflon which has 76% fluorine, thecontact angle is the same as Teflon. Further, the polyurethane elastomerof this invention is clear, making it useful for optical applications.

A 10 mL round bottomed flask was dried under nitrogen and charged withPoly 3 FOX (5.003 g, 1.25 meq), Isonol 93 (26 mg, 0.29 meq), Des-W (214mg, 98%, 1.59 meq), and dibutyltin dilaurate (8 mg). The contents weremixed and casted into a Teflon mold. The mixture was then degassed,placed in an oven, and cured at 65° C. for 8 h. The cured material wasremoved from the mold and characterized as follows:

    ______________________________________                                        Nature:            Tack-free Elastomer                                        Color              Clear, transparent                                         Static Contact Angle (H.sub.2 O)                                                                 110°                                                Mechanical Properties                                                         Tensile Modulus    79 psi                                                     Elongation at Break                                                                              926%                                                       Tensile Strength   670 psi                                                    Hardness           11 Shore A                                                 Glass Transition Temperature, DSC                                                                -40° C.                                             Chemical Resistance                                                           Stable             Methanol, hexane, toluene,                                                    20% Sodium hydroxide & DMF                                 Swell              Freon 113                                                  ______________________________________                                    

EXAMPLE C5 Preparation of Poly 3/15-FOX/Des-W/Isonol PolyurethaneElastomer

This example illustrates the preparation of polyurethane elastomer froma 25:75 Co-prepolymer of 3-(2,2,2-trifluoroethoxymethyl)-3-methyloxetaneand3-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyloxymethyl)-3-methyloxetane(Poly 3/15 FOX, 25:75) by Procedure A.

Note that this Example shows that long side-chains on the prepolymers ofthis invention do not sterically inhibit polymerization. Additionally,the contact angle has increased significantly as a result of thepresence of the long side-chains.

A 50 mL, 3-necked flask was dried with a heat gun under nitrogen andcharged with the poly 3/15-FOX (11.003 g, 3.67 meq), Isonol 93 (74 mg,0.83 meq), Des-W (607 mg, 98.5% pure, 4.53 meq), and dibutyltindilaurate (5.2 mg). The contents were mixed and casted into a Teflonmold. The mixture was then degassed, placed in an oven, and cured at 65°C. for 36 h. The cured material was removed from the mold andcharacterized as follows:

    ______________________________________                                        Nature:            Tack-free Elastomer                                        Color              Opaque                                                     Static Contact Angle (H.sub.2 O)                                                                 128°                                                Mechanical Properties                                                         Tensile Modulus    67 psi                                                     Elongation at Break                                                                              1117%                                                      Tensile Strength   344 psi                                                    Hardness           5 Shore A                                                  Glass Transition Temperature, DSC                                                                -47° C.                                             Water Absorption                                                              9 days/25° C.                                                                             0.20% by Weight Gain                                       16 h/100° C.                                                                              0.22% by Weight Gain                                       Chemical Resistance                                                           Stable             Methanol, hexane, toluene,                                                    20% sodium hydroxide,                                                         carbon tetrachloride,                                                         ethanol, DMSO, non-leaded                                                     gasoline, acetic acid, 3 N                                                    sulfuric acid, & DMF                                       Swell              THF, MTBE and Freon 113                                    ______________________________________                                    

EXAMPLE C6 Preparation of Poly 3/13-FOX/Des-W/Isonol PolyurethaneElastomer

This example illustrates the preparation of polyurethane from a 50:50Co-prepolymer of3-(2,2,3,3,4,4,4-heptafluorobutoxymethyl)-3-methyloxetane and3-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyloxymethyl)-3-methyloxetane(Poly 3/13 FOX, 50:50) by Procedure A.

A 25 mL round bottom flask was dried with a heat gun under nitrogen andcharged with the poly 3/13-FOX (2.36 g, 0.89 meq), Isonol 93 (18 mg,0.20 meq), Des-W (149 mg, 98.5% pure, 1.11 meq), and dibutyltindilaurate (5.2 mg). The contents were mixed and casted into a Teflonmold. The mixture was then degassed, placed in an oven, and cured at 75°C. for 18 h. The polymer sample was removed from the mold andcharacterized as follows:

    ______________________________________                                        Nature:             Tack-free Elastomer                                       Color               Opaque                                                    Contact Angle (H.sub.2 O):                                                                        126°                                               ______________________________________                                    

EXAMPLE C7 Preparation of Poly 3/13/17/21-FOX/N-100 PolyurethaneElastomer

This example illustrates the preparation of polyurethane from aco-prepolymer of3-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyloxymethyl)-3-methyloxetane,3-(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-Heptadecafluorodecyloxymethyl)-3-methyloxetane,and3-(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-Heneicosafluorododecyloxymethyl)-3-methyloxetane(Poly 3/R FOX) by Procedure A. No alcohol or amino-based cross-linkingagent was used. N-100 is a polyisocyanate.

This Example represents the first time a terpolymer using commerciallyavailable alcohols is incorporate_(d) into a polymer matrix. Note theextremely high contact angle of 135° indicating very low surface energyand high hydrophobicity.

A 10 mL beaker was charged with the title terpolymer (2.003 g, 0.80meq), N-100 (151 mg, 0.79 meq), and dibutyltin dilaurate (5.2 mg). Thecontents were mixed and casted into a Teflon mold. The mixture was thendegassed, placed in an oven, and cured at 65° C. for 23 h. The curedmaterial was an opaque, tack-free elastomer, that exhibited a contactangle of 135° with doubly distilled water.

EXAMPLE C8 Preparation of Poly 15-FOX/N-3200 Polyurethane Elastomer

This example illustrates the preparation of polyurethane from thehomo-prepolymer of3-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyloxymethyl)-3-methyloxetane(Poly 15-FOX) by Procedure A. No cross-linking agent was used. N-3200 isa polyisocyanate.

This Example provides guidance in coating a substrate to produce a thin,continuous film, polyurethane coating. Note the extremely high contactangle of 145°.

A 10 mL beaker was charged with the title copolymer (3.200 g, 1.07 meq),N-3200 (212 mg, 1.17 meq), and dibutyltin dilaurate (3 mg). The contentswere mixed, degassed, and spread on an aluminum plate (2"×0.5") with aDoctor's blade to the desired thickness of between 10 to 20 mils. Theplate was placed in an oven and cured at 75° C. for 16 hours. The curedcoating was tack-f=ee, opaque and exhibited a contact angle of 145° withdoubly distilled water. The contact angle of the title elastomer iscompared with the contact angle of Teflon in FIG. 1.

D. FOX/THF CO-PREPOLYMERS and POLYURETHANES

Prepolymers composed of fluorinated polyether segments and hydrocarbonTHF segments may be cured with di- and poly-isocyanates to producefluorinated elastomers having exceptional hydrophobicity and goodphysical and mechanical properties.

The following provide by way of example the methods used synthesize theFOX/THF coprepolymers and the synthesis of the polyurethanes of thisinvention. Examples D1-D5 are directed to the FOX/THF coprepolymersynthesis and Examples D6-D9 are directed to the synthesis of theFOX/THF polyurethane elastomers.

EXPERIMENTAL

¹ H, ¹³ C, and ¹⁹ F NMR analyses were conducted on a 300 MHz, BrukerMSL-300 spectrometer. The proton and carbon chemical shifts are recordedin ppm downfield from tetramethylsilane. Fluorine shifts are reported inppm relative to trichlorofluoromethane. Infrared analyses were conductedon a Nicolet SX 5 spectrometer. Gel Permeation Chromatography wasconducted on a Water's.gel permeation chromatograph equipped with fourultrastyragel columns (100 Å, 500 Å, 1000 Å, and 10,000 Å), a refractiveindex detector, and a Datamodule 730. THF was used as the mobile phase.The GPC was calibrated with a set of well-characterized (i.e., M_(n),M_(w) are well known) polystyrene standards (Narrow Standards), and thusthe number average molecular weight (M_(n)) and weight average molecularweight (M_(w)) are reported relative to polystyrene. Mechanicalproperties were measured With a Model 1122 Instron, and dynamicmechanical properties were measured with Model 660 RehometricsMechanical Spectrometer (RMS). Static contact angles of water withpolymer surfaces were measured with a Goniometer using doubly distilledwater. Differential scanning calorimetry (DSC) and thermogravimetricanalysis (TGA), were performed on a DuPont 990 thermal analyzer system.DSC measurements were made at a heating rate of 10° C./min in air,whereas TGA measurements were made at a heating rate of 20° C./min inair at a flow rate of 20 mL/min. Surface energy was measured by themethod of Wu et al. Inherent viscosity was measured in THF at aConcentration of 0.50 g/dL at 25°C.

Solvents were purchased from Aldrich Chemical Co., and used withoutpurification. Tetrahydrofuran was purified by distillation prior topolymerization. Isocyanates such as Isophorone diisocyanate (IPDI),saturated methylenediphenyldiisocyanate (Des-W), hexamethylenediisocyanate (HDI), and N-3200 (biuret of HDI) were obtained from MobayChemical. Co., and used without further purification. Jeffamines wereobtained from Texaco Oil Co., whereas heptafluorobutan-1-ol waspurchased from Aldrich Chemical Co. BF₃ THF was prepared from BF₃etherate and tetrahydrofuran, and was distilled prior to use.

EXAMPLE D1 Preparation of 7-FOX/THF Co-prepolymer in 60:40 Ratio

This example illustrates the synthesis of a 60:40 co-prepolymer of3-heptafluorobutoxymethyl-3-methyloxetane and Tetrahydrofuran (Poly7-FOX/THF 60:40).

Note that no solvent is used in the preparation of the co-prepolymer.

A 500 mL, 4 necked flask fitted with a mechanical stirrer, condenser,thermometer, and a nitrogen inlet/outlet was charged with freshlydistilled THF (27.0 g, 0.375 moles), butane-1,4-diol (0.50 g, 5.56mmoles), and BF₃ THF (1.90 g, 13.6 mmoles). The mixture was cooled to 8°C., and 3-heptafluorobutoxy-methyl-3-methyloxetane (7-FOX, 70.0 g, 0.246moles) was added, dropwise, over 1.5 h. The temperature was maintainedbelow 12° C., and the progress of the reaction was monitored by ¹ H NMR.The mixture was stirred at room temperature for 2 h and then quenchedwith water (100 mL). The reaction mixture was diluted with methylenechloride (100 mL) and the organic layer was washed with water (200 mL),10% aqueous sodium bicarbonate solution (2×200 mL), water (200 mL), andbrine (200 mL). The mixture was then slowly precipitated into 1.5 L ofmethanol, and the polymer layer was dissolved in methylene chloride (200mL), dried (MgSO₄), filtered, and concentrated on a rotary evaporator togive 107 g (83%) of the title co-prepolymer, an opaque, colorless oil.GPC analysis revealed that the co-prepolymer was devoid of cyclicoligomers. The co-prepolymer was characterized as follows: ¹ H NMR(CDCl₃ /F113) δ: 3.87 (t, J=13.4 Hz), 3.46-3.22 (m, backbone protons),1.61 (br s), and 0.93 (s, --CH₃). (The ratio of 7-FOX units to THFunits, as determined by ¹ H NMR analysis, was 63:37); Equivalent Weightbased on TFAA end group analysis by ¹ H NMR=6,230; Equivalent Weight byp-toluenesulfonyl isocyanate/dibutyl amine titration=5,890; ¹³ C NMR δ:17.13, 25.56, 26.71, 41.24, 41.40, 41.55, 68.45 (t), 70.75, 71.38,73.29, 73.93, and 75.75 (signals from carbons bearing fluorine are notincluded); ¹⁹ F NMR δ: -81.2 (3F), -121.0 (2F), and -127.7 (2F); GPC:M_(n) =13,363, M_(w) =25,526, Polydispersity=1.91; InherentViscosity=0.125 dL/g; DSC: T_(g) =-43° C.

EXAMPLE D2 Preparation of 7-FOX/THF Co-prepolymer in 90:10 Ratio

This example illustrates the synthesis of a 90:10 co-prepolymer of3-Heptafluorobutoxymethyl-3-Methyloxetane and Tetrahydrofuran (Poly7-FOX/THF 90:10).

A 50 mL, 3 necked flask fitted with a mechanical stirrer, condenser,thermometer, and a nitrogen inlet/outlet was charged with methylenechloride (9 mL), 1,4 butanediol (62 mg, 0.69 mmole), and BF₃ THF (260mg, 1.86 mmole). After stirring at room temperature for 30 minutes, themixture was heated to reflux for 5 minutes and then cooled to 8° C.Next, a solution of 3-heptafluorobutoxymethyl-3-methyloxetane (7-FOX,10.2 g, 35.9 mmoles) in Freon 113 (3 mL) was added over a period of 15minutes. The resulting mixture was stirred at room temperature for 1 h,diluted with methylene chloride (20 mL) and Freon 113 (10 mL), andquenched with water. The organic layer was washed with 10% aqueoussodium bicarbonate solution (50 mL), water (50 mL), and brine (50 mL),dried (MgSO₄), filtered, and concentrated on a rotary evaporator to give10.3 g (96.3%) of the title co-prepolymer, a clear, colorless oil. GPCanalysis indicated that the co-prepolymer was contaminated with ca. 1.3%of cyclic tetramer. The co-prepolymer was characterized as follows: ¹ HNMR (CDCl₃ /F113) δ0.95 (s), 1.64 (broad), 3.25-3.37 (m), 3.48 (s), and3.89 (t, J=13.60 Hz) (The ratio of 7-FOX units to THF units, asdetermined by ¹ H NMR analysis, was 90:10); Equivalent weight based onTFAA end group analysis by ¹ H NMR=6,649; ¹³ C NMR (CDCl₃ /F113) δ17.08,26.54, 26.69, 41.25, 41.41, 41.57, 41.81, 68.49 (t), 70.73, 71.39,73.30, 73.52, 74.00, and 75.79 (signals from carbon bearing fluorinesare not included due to complex splitting patterns and low peakintensities); GPC: M_(n) =11,586, M_(n) =23,991, Polydispersity=2.07;DSC, T_(g) =-41° C.

EXAMPLE D3 Preparation of 7-FOX/THF Co-prepolymer in 35:65 Ratio

This example illustrates the synthesis of a 35:65 co-prepolymer of3-Heptafluorobutoxymethyl-3-methyloxetane and Tetrahydrofuran (Poly7-FOX/THF 35:65).

Note that no solvent is used in this Example and that no cyclic tetramerwas detected.

A 100 mL round bottomed flask fitted with a reflux condenser, nitrogeninlet/outlet, thermometer and an addition funnel was charged withfreshly distilled THF (25 mL, 22.2 g, 308 mmol), BF₃ THF (366 mg, 2.6mmol), and 1,4-butanediol (90 mg, 1.0 mmol). The mixture was stirred atroom temperature for 10 mins, cooled to 10° C. and treated, dropwise,with 3-heptafluorobutoxymethyl-3-methyloxetane (7-FOX, 10.2 g, 35.9mmol) over a period of 10 mins. The mixture was stirred at 10° C. for 10mins and then at room temperature for 2 days. The progress of thereaction was monitored by ¹ H NMR. The reaction mixture was diluted withmethylene chloride and Freon 113 (60:40), and then quenched with water(10 mL). The organic layer was separated and washed with water (30 mL),10% aqueous sodium bicarbonate solution (30 mL), water (30 mL), andbrine (30 mL). The organic layer was dried (MgSO₄), filtered, andconcentrated under reduced pressure to give 16.2 g of the titleco-prepolymer, a colorless, viscous oil. GPC analysis indicated that theco-prepolymer was devoid of cyclic oligomers. The co-prepolymer wascharacterized as follows: ¹ H NMR (CDCl₃) δ0.95 (s), 1.63-1.64 (br s),3.24 (s), 3.42-3.48 (m), and 3.87 (t) (The ratio of 7-FOX units to THFunits by ¹ H NMR was 66:34); Equivalent weight based on TFAA end groupanalysis by ¹ H NMR=6,104; ¹³ C NMR 17.32, 26.93, 27.08, 41.59, 41.76,41.95, 68.89 (t), 70.88, 71.67, 73.65, 74.34, 74.39, 76.22, and 76.57(signals from carbon bearing fluorines are not included due to complexsplitting patterns and low peak intensities); GPC: M_(n) =12,576, M_(w)=20,018, and Polydispersity=1.59.

EXAMPLE D4 Preparation of 13-FOX/THF Co-prepolymer in 50:50 Ratio

This example illustrates the synthesis of a 50:50 co-prepolymer of3-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyloxymethyl)-3-methyloxetaneand Tetrahydrofuran (Poly 13-FOX/THF 50:50).

This is another example of a FOX/THF co-prepolymer with the FOX monomershaving long fluorinated side-chains. As in the previous Example C5, thepresence of the long side-chains unexpectedly do not hinder thepolymerization. Further, unlike the polymerization of the bis-monomers,no cyclic tetramers were detected. No solvent was used in thispolymerization.

A 250 mL, 3-necked, round-bottom flask fitted with a condenser, athermometer, a nitrogen inlet/outlet, and an addition funnel was chargedwith freshly distilled tetrahydrofuran (36 g, 0.5 mol), 1,4-butanediol(68 mg, 0.75 mmol), and boron trifluoride tetrahydrofuranate (250 mg,1.786 mmol). The solution was cooled to 10° C. and3-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyloxymethyl)-3-methyloxetane(13-FOX, 35.3 g, 78.8 mmol) was added over a period of 45 mins. Themixture was stirred at 10° C. for 3 h and then at room temperature for16 h. ¹ H NMR of an aliquot revealed that the reaction of ca. 90%complete. The reaction mixture was then heated at reflux for 2 h, atwhich point NMR analysis indicated >95% completion. Water was added andthe organic layer was slowly precipitated into methanol. Theprecipitated material was dissolved in 1:1 Freon 113/methylene chloride,dried (MgSO₄), filtered, and concentrated on a rotary evaporator to give36.5 g (89%) of the title prepolymer, a viscous oil. GPC analysis of theprepolymer revealed total absence of cyclic oligomers. The prepolymerwas characterized as follows: ¹ H NMR 3.67 (t), 3.42 (br s), 3.32-3.21(m), 2.36 (tt), 1.63 (br s), and 0.93 (s). (The ratio of 13-FOX units toTHF units by ¹ H NMR was 50:50); Equivalent weight based on TFAA endgroup analysis by ¹ H NMR=8,903; GPC: Mn=25,244, Mw=35,968,Polydispersity=1.43; ¹³ C NMR 17.53, 26.95, 27.07, 32.07 (t), 41.30,41.50, 41.7.1, 63.55, 71.0, 71.62, 71.89, 73.88, 74.41, and 75.35(signals from carbon bearing fluorines are not included due to complexsplitting patterns and low peak intensities).

EXAMPLE D5 Preparation of 15-FOX/THF Co-prepolymer in 60:40 Ratio

This example illustrates the synthesis of a 60:40 co-prepolymer of3-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-Pentadecafluorooctyloxymethyl)-3-methyloxetaneand Tetrahydrofuran (Poly 15-FOX/THF 60:40).

This is another example of a FOX/THF co-prepolymer with the FOX monomershaving long fluorinated side-chains. As in the previous Examples C5 andD4, the presence of the long side-chains unexpectedly do not hinder thepolymerization. Further, unlike the polymerization of the bis-monomers,no cyclic tetramers were detected.

No solvent was used in this polymerization.

A 200 mL, 3-necked round bottomed flask fitted with a reflux condenser,nitrogen inlet/outlet, a magnetic stirring bar, a thermometer and anaddition funnel was charged with anhydrous THF (18.14 g, 0.25 mol),1,4-butanediol (25.7 mg, 0.29 mmol), and boron trifluoridetetrahydrofuranate (100 mg, 0.71 mmol). The mixture was cooled to 5° C.and3-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyloxymethyl)-3-methyloxetane(15-FOX, 20.0 g, 41.3 mmol) was added over a period of 10 mins. Themixture was stirred at room temperature for 2 days, quenched with water(2 mL), and slowly precipitated into methanol. The precipitated materialwas dissolved in a 1:1 mixture of methylene chloride and Freon 113,dried, filtered and concentrated on a rotary evaporator to give 17.3 gof the title co-prepolymer, a viscous, colorless oil. The ratio of the15-FOX units to THF units, as determined by ¹ H NMR analysis, was 59:41.The co-prepolymer was characterized as follows: ¹ H NMR δ3.89 (t, 13.5HZ), 3.48-3.41 (m), 3.24 (s), 1.63 (s), and 0.95.(s); Equivalent Weightbased on TFAA end group analysis by ¹ H NMR=9,321; ¹³ C NMR δ17.27,26.86, 27.02, 41.51, 41.68, 41.85, 69.01 (t), 70.94, 71.57, 73.55,74.18, and 76.09.

Polyurethanes from FOX/THF Co-prepolymers EXAMPLE D6 Preparation of Poly7-FOX/THF Based Polyurethane

This example illustrates the preparation of a polyurethane from Poly60:40 7-FOX/THF and Des-W. Note that although the incorporation of THFinto the prepolymer backbone results in 40% less fluorine than in a7-FOX prepolymer (no THF), the contact angle and T_(g) of the 7-FOX/THFpolyurethane is comparable to the polyurethane derived from the 7-FOXprepolymer.

A 50 mL, 3-necked flask was dried with a heat gun under nitrogen andcharged with poly 60:40 7-FOX/THF (11.00 g, 3.16 meq), Isonol 93 (64 mg,0.73 m eq), Des-W (524 mg, 3.89 meq), and dibutyltin dilaurate (5 mg).The contents were mixed, casted into a Teflon mold, and degassed underreduced pressure for 15 mins. The mixture was then cured in an oven,under nitrogen, at 65° C. for 16 h. The cured material was removed fromthe mold and characterized as follows:

    ______________________________________                                        Nature:                Opaque, Tack-free                                                             Elastomer                                              Contact Angle (H.sub.2 O)                                                                            117°                                            Surface Energy         13.5 ergs/cm.sup.2                                     Mechanical Properties                                                         Tensile Modulus        53 psi                                                 Elongation at Break    1624%                                                  Tensile Strength       624 psi                                                Glass Transition Temperature, DSC                                                                    -43° C.                                         Peel Strength, EPDM Rubber Substrate                                                                 >10 lb/in,                                                                    Cohesive Failure                                       ______________________________________                                    

EXAMPLE D7 Preparation of a Coating From Poly 7-FOX/THF Polyurethane

This Example is the same as Example D6, except that it teaches theprocess for coating a substrate with a thin film of fluorinatedpolyurethane prepared from poly-7-FOX/THF (60:40), Des-W and Isonol 93.

A 50 ml, 3-necked flask was dried with a heat gun under nitrogen andcharged with poly7-FOX/THF (60:40, 11.0 g, 3.16 meq)), Des-W (524 mg,3.89 meq), Isonol 93 (64 mq, 0.73 meq) and dibutyltin dilaurate (5 mg).The contents were mixed, diluted with anhydrous THF (10 ml) and spreadon a stainless steel substrate with a Doctor's blade. Alternately, thesubstrate can be dipped, or spray coated with the above formulation. Thecoated substrate was dried in a hood for 4 hours and then heated in anoven at 40° C. for 2 hours and then at 65° C. for 16 hours. The curedcoating was a continuous, tack-free film, and exhibited a contact angleof 118° with doubly distilled water.

EXAMPLE D8 Preparation of Poly 7-FOX/THF Polyurethane in 35:65 Ratio

This example illustrates the preparation of a polyurethane from Poly35:65 7-FOX/THF, Des-W and Isonol 93.

In a manner similar to that described in Example D6, a mixture of poly35:65 7-FOX/THF (10.02 g, 2.50 meq), Isonol 93 (53 mg, 0.60 m eq), Des-W(417 mg, 98% pure, 3.10 meq), and dibutyltin dilaurate (1 drop) wascured in a Teflon mold at 65° C. for 16 h. The cured material wasremoved from the mold and characterized as follows:

    ______________________________________                                        Nature:              Translucent, Tack-free                                                        Elastomer                                                Contact Angle (H.sub.2 O)                                                                          108°                                              Mechanical Properties                                                         Tensile Modulus      205 psi                                                  Elongation at Break  420%                                                     Tensile Strength     571 psi                                                  Glass Transition Temperature, DSC                                                                  -41° C.                                           ______________________________________                                    

EXAMPLE D9 Preparation of Poly 15-FOX/THF Polyurethane

This example illustrates the preparation of a polyurethane from Poly60:40 15-FOX/THF and N-3200. Note that the contact angle of theresulting polyurethane was very high (126°) despite dilution of thepolymer with the THF segments. Further, there was no change in T_(g). Incomparison, the non-diluted 15-FOX polyurethane of Example C8 exhibitedthe highest contact angle ever observed of 145°.

In a manner similar to that described in Example D6, a mixture of poly60:40 15-FOX/THF (3.0 g, 0.73 meq), N-3200 (135 mg, 0.73 meq), THF (0.5mL), and dibutyltin dilaurate (3 mg), were cured in a Teflon mold, undernitrogen, at 75° C. for 3 days. The cured material was an opaque, tackfree elastomer, with following properties: T_(g) (DSC)=-46° C.; ContactAngle with Water=126°.

EXAMPLE D10 Preparation of Poly 13-FOX/THF Polyurethane

This example illustrates the preparation of a polyurethane from Poly50:50 13-FOX/THF and Des-W

In a manner similar to that described in Example D6, a mixture of poly50:50 13-FOX/THF (5.002 g, 1.50 meq), Isonol 93 (5.3 mg, 0.06 meq),Des-W (210 mg, 98% pure, 1.56 meq), and dibutyltin dilaurate (4 mg) wascured at 65° C. for 2 days. The cured material was an opaque, tack freeelastomer with following properties: Tg (DSC)=-43° C.; Contact Anglewith Water=123° C.; Mechanical Properties: Tensile Modulus=35 psi,Elongation at Break=972%, Tensile Strength=487 psi.

It should be understood that various modifications within the scope ofthis invention can be made by one of ordinary skill in the art withoutdeparting from the spirit thereof. We therefore wish our invention to bedefined by the scope of the appended claims as broadly as the prior artwill permit, and in view of the specification if need be.

We claim:
 1. A method of using a mono-substituted fluorinated oxetane(FOX) monomer to make a FOX/THF co-prepolymer, said FOX monomer havingthe structure: ##STR13## where n is 1 to 3, R is methyl or ethyl, andR_(f) is linear or branched chain perfluorinated alkyl or isoalkylhaving from 1 to 20 carbons or an oxa-perfluorinated polyether, havingfrom 4 to about 60 carbons, comprising the steps of:a) providing neattetrahydrofuran (THF) or forming a mixture of THF in an organic solvent;b) maintaining said neat THF or THF mixture at a temperature in therange of from about -20° C. to about +60° C.; c) contacting said neatTHF or THF mixture with a Lewis acid catalyst and water or a polyhydroxyaliphatic compound as an initiator; d) adding at least one FOXmonomer(s) to said neat THF or THF mixture to form a reaction mixture;and e) maintaining said reaction mixture at a temperature in range offrom about -20° C. to about +60° C. for a time sufficient to producesaid FOX/THF co-prepolymer.
 2. A method of using a mono-substitutedfluorinated oxetane monomer as in claim 1, wherein:said organic solventis selected from the group consisting of methylene chloride, carbontetrachloride, chloroform, trichloroethylene, chlorobenzene, ethylbromide, dichloroethane, trichlorotrifluoroethane, fluorinated solventsand mixtures thereof.
 3. A method of using a mono-substitutedfluorinated oxetane monomer as in claim 1, wherein:said catalyst is aLewis acid selected from the group consisting of boron trifluorideetherate, boron trifluoride tetrahydrofuranate, phosphorouspentafluoride, antimony pentafluoride, zinc chloride, aluminum bromideand mixtures thereof.
 4. A method of using a mono-substitutedfluorinated oxetane monomer as in claim 1, wherein:said initiator is apolyhydroxy aliphatic compound having from about 2 to about 5 carbonsand from about 2 to 4 hydroxy groups.
 5. A method of using amono-substituted fluorinated oxetane monomer as in claim 4, wherein:a)said initiator is selected from the group consisting of ethylene glycol;butane-1,4-diol; isobutane-1,3-diol; pentane-1,5-diol; pentaerythritol;trimethylolpropane and mixtures thereof, and b) includes the added stepof recovering as a reaction product a FOX/THF co-prepolymer from saidreaction mixture.
 6. A method of using a mono-substituted fluorinatedoxetane monomer as in claim 1, wherein said FOX monomer added to saidneat THF or THF mixture is selected from the group consisting of3-(2,2,2-trifluoroethoxymethyl)-3-methyloxetane,3-(2,2,3,3,4,4,4-heptafluorobutoxymethyl)-3-methyloxetane,3-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyloxymethyl)-3-methyloxetane,3-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyloxymethyl)-3-methyloxetane,3-(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyloxymethyl)-3-methyloxetane,3-(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-heneicosafluorododecyloxymethyl)-3-methyloxetane,and mixtures thereof.
 7. A method for using a mono-substitutedfluorinated oxetane monomer as in claim 5, wherein said FOX/THFco-prepolymer is selected from the group consisting ofpoly-3-(2,2,2-trifluoroethoxymethyl)-3-methyloxetane/THF co-prepolymer,poly-3-(2,2,3,3,4,4,4heptafluorobutoxymethyl)-3-methyloxetane/THFco-prepolymer,poly-3-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyloxymethyl)-3methyloxetane/THF co-prepolymer,poly-3(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyloxymethyl)/THFco-prepolymer, and mixtures thereof.
 8. A method of using amono-substituted fluorinated oxetane monomer as in claim 2, wherein neatTHF is provided.
 9. A process for producing a FOX/THF co-prepolymerhaving the structure: ##STR14## wherein: n is 1 to 3;R is selected fromthe group consisting of methyl and ethyl; R_(f) is selected from thegroup consisting of linear and branched chain perfluorinated alkyl orisoalkyl groups having from 1 to 20 carbons and an oxa-perfluorinatedpolyether, having from 4 to about 60 carbons; and R₁ is selected fromthe group consisting of H and a polyhydroxy aliphatic compound havingfrom 2 to about 5 carbons and from about 2 to about 3 hydroxy groups;said process comprising the steps of: a) providing neat THF or premixingTHF in an appropriate organic solvent, wherein the THF and solventtemperature is between -20° C. and +60° C. and the solvent concentrationis from 0% to 90% v/v; b) adding a Lewis acid catalyst; c) adding wateror a polyhydroxy aliphatic compound as an initiator; and d) adding a FOXmonomer(s), wherein the temperature of said FOX monomer(s) is between-20° C. and +60° C.
 10. A process for producing a FOX/THF co-prepolymeras in claim 9, wherein said organic solvent is selected from the groupconsisting of carbon tetrachloride, chloroform, trichloroethylene,chlorobenzene, ethyl bromide, dichloroethane, fluorinated solvents,sulfur dioxide, hexanes, petroleum ether, toluene, dioxane, xylene,methylene chloride, Freon 113 and mixtures thereof.
 11. A process forproducing a FOX/THF co-prepolymer as in claim 9, wherein neat THF isprovided.
 12. A process for producing a FOX/THF co-prepolymer as inclaim 9, wherein said Lewis acid is selected from the group consistingof complexes of boron trifluoride, phosphorous pentafluoride, SnCl₄,antimony pentafluoride and mixtures thereof.
 13. A process for producinga FOX/THF co-prepolymer as in claim 9, wherein said initiator isselected from the group consisting of water, 1,4-butanediol,trimethylolpropane, pentaerythritol and mixtures thereof.
 14. A processfor producing a FOX/THF co-prepolymer as in claim 13, wherein saidsolvent is selected from the group consisting of carbon tetrachloride,chloroform, trichloroethylene, chlorobenzene, ethyl bromide,dichloroethane, fluorinated solvents, sulfur dioxide, hexanes, petroleumether, toluene, dioxane, xylene, methylene chloride, Freon 113 andmixtures thereof.
 15. A process for producing a FOX/THF co-prepolymer asin claim 9, which includes the additional step of recovering as areaction product said FOX/THF co-prepolymer from the reaction mixture.16. A process for producing a FOX/THF co-prepolymer as in claim 9wherein said FOX monomer is selected from the group consisting of3-(2,2,2-trifluoroethoxymethyl)-3-methyloxetane,3-(2,2,3,3,4,4,4-heptafluorobutoxymethyl)-3-methyloxetane,3-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyloxymethyl)-3methyloxetane,3-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyloxymethyl)-3-methyloxetane,3-(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyloxymethyl)-3-methyloxetane,3-(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-heneicosafluorododecyloxymethyl)-3-methyloxetane,and mixtures thereof.
 17. A process for producing a FOX/THFco-prepolymer as in claim 15 wherein said FOX/THF co-prepolymer isselected from the group consisting ofpoly-3-(2,2,2-trifluoroethoxymethyl)-3-methyloxetane/THF co-prepolymer,poly-3-(2,2,3,3,4,4,4heptafluorobutoxymethyl)-3-methyloxetane/THFco-prepolymer,poly-3-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyloxymethyl)-3-methyloxetane/THFco-prepolymer,poly-3-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctyloxymethyl)-3-methyloxetane/THFco-prepolymer, and mixtures thereof.